a. The dotplot of the difference (A-P) in time spent online shows that most parents underestimated the amount of time their children spent online during the 6-month period. The majority of the differences are positive, indicating that the actual time spent online was greater than the parents' perception.
How to determine the mean difference?b. The mean difference (A-P) in time spent online is (7.1-5.9+5.2-6.2+5.8-4.7+2.5-8.2+3-6.4)/10 = -0.3 hours per day. The standard deviation of the differences can be calculated using a formula or a calculator, and it is approximately 2.82 hours per day. This means that the average difference between the actual time spent online and the parents' perception was a small underestimate of 0.3 hours per day, with a variation of approximately 2.82 hours per day.
c. To construct a 90% confidence interval for the true mean difference (A-P) in time spent online, we can use the formula:
mean difference ± t-value (with 9 degrees of freedom) x (standard deviation / square root of sample size)
Using a t-table, the t-value for a 90% confidence interval with 9 degrees of freedom is approximately 1.83. The standard error of the mean difference is the standard deviation divided by the square root of the sample size, which is 2.82 / sqrt(10) = 0.89. Therefore, the 90% confidence interval for the true mean difference is:
-0.3 ± 1.83 x 0.89
This simplifies to -0.3 ± 1.63, or (-1.93, 1.33) hours per day. This means that we are 90% confident that the true mean difference between the actual time spent online and the parents' perception falls within this interval. Since the interval includes zero, we cannot reject the null hypothesis that there is no difference between the actual time spent online and the parents' perception at the 5% level of significance. However, the interval suggests that there could be a small underestimate or overestimate of the actual time spent online by the parents.
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Cheddar cheese costs 55p per 100g. Swiss cheese costs 60p per 100g. Zac spen a total of £3. 15 on cheese. He bought 300g of Cheddar. How many grams of swiss cheese did he buy
Zac bought 250 grams of Swiss cheese.
To find out how many grams of Swiss cheese Zac bought, let's follow these steps:
Calculate the cost of Cheddar cheese: 300g of Cheddar cheese costs 55p per 100g,
so (300g / 100g) × 55p = 3 × 55p = 165p.
Convert the total amount spent on cheese to pence:
£3.15 = 315p.
Subtract the cost of Cheddar cheese from the total amount spent:
315p - 165p = 150p.
Calculate the grams of Swiss cheese:
Since Swiss cheese costs 60p per 100g, divide the remaining cost by the price per 100g:
150p / 60p = 2.5.
Multiply the result by 100g to find the total grams of Swiss cheese:
2.5 × 100g = 250g.
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The probability of a three of a kind in poker is approximately 1/50. Use the Poisson approximation to estimate the probability you will get at least one three of a kind if you play 20 hands of poker.
The probability of getting at least one three of a kind in 20 hands of poker, using the Poisson approximation, is approximately 0.3293 or about 32.93%.
What is probability?
Probability is a branch of mathematics that deals with the study of random events or processes. It is the measure of the likelihood that an event will occur, expressed as a number between 0 and 1, where 0 means that the event will not occur and 1 means that the event is certain to occur.
We can use the Poisson distribution to approximate the probability of getting at least one three of a kind in 20 hands of poker, given that the probability of a three of a kind is approximately 1/50.
Let λ be the expected number of three of a kinds in 20 hands. Then λ = np, where n is the number of hands (20) and p is the probability of a three of a kind (1/50).
λ = np = 20 * (1/50) = 0.4
Using the Poisson distribution, the probability of getting k three of a kinds in 20 hands is given by:
[tex]P(k) = (e^{(-\lambda)} * \lambda^k) / k![/tex]
The probability of getting at least one three of a kind in 20 hands is:
P(at least one three of a kind) = 1 - P(0 three of a kinds)
[tex]= 1 - (e^(-0.4) * 0.4^0) / 0!\\\\= 1 - e^(-0.4)[/tex]
≈ [tex]0.3293[/tex]
Therefore, the probability of getting at least one three of a kind in 20 hands of poker, using the Poisson approximation, is approximately 0.3293 or about 32.93%.
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let abcd be a parallelogram. prove: abcd is a rectangle iff ac = bd
We have shown that a parallelogram ABCD is a rectangle if and only if AC = BD.
What is triangle?
A triangle is a three-sided polygon with three angles. It is a fundamental geometric shape and is often used in geometry and trigonometry.
To prove that a parallelogram ABCD is a rectangle if and only if AC = BD, we need to show two things:
If ABCD is a rectangle, then AC = BD.
If AC = BD, then ABCD is a rectangle.
Proof:
1. Assume that ABCD is a rectangle. This means that all angles of the parallelogram are right angles. Let's draw diagonal AC and BD, which divide the rectangle into four right triangles (ABC, BCD, ACD, and ABD). Since the opposite sides of a parallelogram are congruent, we have AB = CD and AD = BC. Therefore, triangles ABD and ACD are congruent (by side-angle-side) and have the same hypotenuse AD. This means that their legs are congruent: AB = CD and BD = AC. Since AB = CD, we have AC + BD = AD + AD = 2AD. But since ABCD is a rectangle, we know that AC = AD and BD = AD. Therefore, AC + BD = 2AD = 2AC = 2BD. So AC = BD.
2. Now assume that AC = BD. We need to prove that ABCD is a rectangle. Let's draw diagonal AC and BD again. Since AC = BD, the two diagonals divide the parallelogram into four congruent triangles (ABC, ACD, BCD, and ABD). Therefore, each of these triangles has a right angle, since the sum of their angles is 180 degrees. Since angle BCD and angle ACD are adjacent angles around a straight line, they add up to 180 degrees, so they are also right angles.
Therefore, we have shown that a parallelogram ABCD is a rectangle if and only if AC = BD.
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find the value of each of the six trigonometric functions for the angle, in standard position, whose terminal side passes through the given point. (if an answer is undefined, enter undefined.) P= (-8 , 5). Sin 0 = ___ . Cos 0 = ____. Tan 0 = ____. Csc 0 = ____. Sec 0 = ___. Cot 0 = ____.
sec θ = -√89/8
cot θ = -8/5
We can use the distance formula to find the hypotenuse of the right triangle formed by the terminal side passing through point P(-8, 5):
h = √(x^2 + y^2) = √((-8)^2 + 5^2) = √(64 + 25) = √89
Now we can use the definitions of the trigonometric functions to find their values:
sin θ = y/h = 5/√89
cos θ = x/h = -8/√89 (negative because x is negative in the second quadrant)
tan θ = y/x = -5/8 (negative because both x and y are in opposite quadrants)
csc θ = h/y = √89/5
sec θ = h/x = -√89/8 (negative because x is negative in the second quadrant)
cot θ = 1/tan θ = -8/5 (negative because both x and y are in opposite quadrants)
Therefore, the values of the six trigonometric functions for the angle whose terminal side passes through point P(-8, 5) are:
sin θ = 5/√89
cos θ = -8/√89
tan θ = -5/8
csc θ = √89/5
sec θ = -√89/8
cot θ = -8/5
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For random samples of size n=16 selected from a normal distribution with a mean of μ = 75 and a standard deviation of σ = 20, find each of the following: The range of sample means that defines the middle 95% of the distribution of sample means
The range of sample mean is that it defines the middle 95% of the distribution of sample mean is from 68.2 to 81.8. This means that if we were to take multiple random samples of size 16 from the population, 95% of the sample means would fall within this range.
To find the range of sample means that defines the middle 95% of the distribution of sample means, we can use the formula:
range = (X - zα/2 * σ/√n, X + zα/2 * σ/√n)
where X is the sample mean, σ is the population standard deviation, n is the sample size, and zα/2 is the z-score that corresponds to the desired confidence level and is found using a standard normal distribution table.
For a 95% confidence level, zα/2 = 1.96. Substituting the given values into the formula, we get:
range = (75 - 1.96 * 20/√16, 75 + 1.96 * 20/√16)
range = (68.2, 81.8)
Therefore, the range of sample means that defines the middle 95% of the distribution of sample means is from 68.2 to 81.8. This means that if we were to take multiple random samples of size 16 from the population, 95% of the sample means would fall within this range.
To find the range of sample means that defines the middle 95% of the distribution of sample means, we need to use the Central Limit Theorem and calculate the standard error.
Given a normal distribution with mean (μ) = 75, standard deviation (σ) = 20, and sample size (n) = 16, we can calculate the standard error (SE) using the following formula:
SE = σ / √n
SE = 20 / √16
SE = 20 / 4
SE = 5
Now, we need to find the critical z-score for a 95% confidence interval. For a 95% confidence interval, the critical z-score (z*) is approximately ±1.96.
Next, we'll use the critical z-score to find the margin of error (ME):
ME = z* × SE
ME = 1.96 × 5
ME = 9.8
Finally, we'll calculate the range of sample means:
Lower limit = μ - ME = 75 - 9.8 = 65.2
Upper limit = μ + ME = 75 + 9.8 = 84.8
The range of sample means that defines the middle 95% of the distribution of sample means is approximately 65.2 to 84.8.
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State if the triangle is acute obtuse or right
Answer: Right
Step-by-step explanation: You have 3 angles, two are less than 90 degrees while the other is exactly 90, that would make this a right triangle.
Peter needs to borrow $10,000 to repair his roof. He will take out a 317-loan on April 15th at 4% interest from the bank. He will make a payment of $3,500 on October 12th and a payment of $2,500 on January 11th.
a) What is the due date of the loan?
b) Calculate the interest due on October 12th and the balance of the loan after the October 12th payment.
a) The due date of the loan is April 15th of the following year.
b) The interest due on October 12th is $200 and the balance of the loan after the October 12th payment is $6,700.
Define interest rate?The percentage amount a lender charges a borrower for using money or the amount a saver earns for depositing money in a bank or other financial institution is known as an interest rate.
a) Let's assume that the loan term is 12 months.
The loan is taken out on April 15th, so the due date will be 12 months later, which is:
April 15th + 12 months = April 15th of the following year.
Therefore, the due date of the loan is April 15th of the following year.
b) The interest for the 6 months between April 15th and October 12th is:
Interest = Principal x Rate x Time
= $10,000 x 0.04 x (6/12)
= $200
Therefore, the interest due on October 12th is $200.
The payment made on October 12th is $3,500, so the remaining balance of the loan after that payment is:
Balance = Principal + Interest - Payment
= $10,000 + $200 - $3,500
= $6,700
So, the balance of the loan after the October 12th payment is $6,700.
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.if the r.v x is distributed as uniform distribution over [-a,a], where a > 0. determine the parameter a, so that each of the following equalities holds a.P(-1 2)
Both equalities hold true for any value of a > 0, as the probability of a continuous random variable taking any specific value is always 0.
Given that the random variable x is uniformly distributed over the interval [-a,a], the probability density function (PDF) of x is given by:
f(x) = 1/(2a), for -a ≤ x ≤ a
f(x) = 0, otherwise
To determine the parameter a, we need to use the given equalities:
a. P(-1 < x < 1) = 0.4
The probability of x lying between -1 and 1 is given by:
P(-1 < x < 1) = ∫(-1)^1 f(x) dx
= ∫(-1)^1 1/(2a) dx
= [x/(2a)]|(-1)^1
= 1/(2a) + 1/(2a)
= 1/a
Therefore, we have:
1/a = 0.4
a = 1/0.4
a = 2.5
So, for the equality P(-1 < x < 1) = 0.4 to hold, the parameter a should be 2.5.
b. P(|x| < 1) = 0.5
The probability of |x| lying between 0 and 1 is given by:
P(|x| < 1) = ∫(-1)^1 f(x) dx
= ∫(-1)^0 f(x) dx + ∫0^1 f(x) dx
= [x/(2a)]|(-1)^0 + [x/(2a)]|0^1
= 1/(2a) + 1/(2a)
= 1/a
Therefore, we have:
1/a = 0.5
a = 1/0.5
a = 2
So, for the equality P(|x| < 1) = 0.5 to hold, the parameter a should be 2.
c. P(x > 2) = 0
The probability of x being greater than 2 is given by:
P(x > 2) = ∫2^a f(x) dx
= ∫2^a 1/(2a) dx
= [x/(2a)]|2^a
= (a-2)/(2a)
For the equality P(x > 2) = 0 to hold, we need:
(a-2)/(2a) = 0
a - 2 = 0
a = 2
So, for the equality P(x > 2) = 0 to hold, the parameter a should be 2.
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The matrix A = [ ] has eigenvalues -3, -1, and 5. Find its eigenvectors. The eigenvalue -3 is associated with eigenvector ( 1, 1/14 ,-4/7 ). The eigenvalue -1 is associated with eigenvector ( , , ). The eigenvalue 5 is associated with eigenvector ( , ).
Eigenvectors associated with -3, -1, and 5 are (1, 1/14, -4/7), (-1, 1, 0), and (1, 1, 0), respectively.
How to find the eigenvectors associated with eigenvalues -1 and 5?We need to solve the system of equations:
(A - λI)x = 0
λ is eigenvalue
I is identity matrix.
For λ = -1:
(A + I)x = 0
[2 2 2]
[2 2 2]
[2 2 2]
R2 <- R1
[2 2 2]
[0 0 0]
[2 2 2]
R3 <- R1 - R3
[2 2 2]
[0 0 0]
[0 0 0]
So we have the equation 2x + 2y + 2z = 0, which simplifies to x + y + z = 0. We can choose y = 1 and z = 0 to get x = -1, so the eigenvector associated with -1 is (-1, 1, 0).
For λ = 5:
(A - 5I)x = 0
[-2 2 2]
[2 -2 2]
[2 2 -8]
R1 <-> R2
[2 -2 2]
[-2 2 2]
[2 2 -8]
R3 <- R1 + R3
[2 -2 2]
[-2 2 2]
[4 0 -6]
R1 <- R1/2
[1 -1 1]
[-2 2 2]
[4 0 -6]
R2 <- R2 + 2R1
[1 -1 1]
[0 0 4]
[4 0 -6]
R3 <- R3 - 4R1
[1 -1 1]
[0 0 4]
[0 4 -10]
R3 <- R3/2
[1 -1 1]
[0 0 4]
[0 2 -5]
So we have the equation x - y + z = 0 and 4z = 0. We can choose y = 1 and z = 0 to get x = 1, so the eigenvector associated with 5 is (1, 1, 0).
Therefore, the eigenvectors associated with -3, -1, and 5 are (1, 1/14, -4/7), (-1, 1, 0), and (1, 1, 0), respectively.
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find the area of the region between the following curves by integrating with respect to y . if necessary, break the region into subregions first. x = y − y 2 and x = − 3 y 2
Answer:
0.0417 unit^2.
Step-by-step explanation:
First find the points at which the curves intersect
x = y - y^2
x = -3y^2
---> y - y^2 = -3y^2
---> 2y^2 + y = 0
---> y(2y + 1)= 0
y = -0.5, 0.
At these values x = -0.75 and 0.
The points of intersection are (0, 0) and (-0.75, -0.5)
The required area
-0.5
= ∫ -3y^2 - ∫y - y^2
0
= [ -y^3 - (y^2/2 - y^3/3)] between limits -0.5 and 0
= [0.125 - ( 0.125 - (-0.125/3)]
= -0.0417
We take the positive value 0.0417.
find the absolute maxima and minima for f(x) on the interval [a, b]. f(x) = 2x3 − 3x2 − 36x − 9, [−10, 10] absolute minimum (x, y) = absolute maximum (x, y) =
To find the absolute maxima and minima for f(x) = 2x^3 - 3x^2 - 36x - 9 on the interval [-10, 10], follow these steps:
Find the derivative, f'(x), to identify critical points: f'(x) = 6x^2 - 6x - 36. Set f'(x) = 0 and solve for x to find critical points: 6x^2 - 6x - 36 = 0.
3. Factor the equation: 6(x^2 - x - 6) = 0, then solve for x: x = -2, x = 3 (critical points). Evaluate f(x) at critical points and endpoints: f(-10), f(-2), f(3), f(10). Compare values to find the absolute minimum and maximum:
f(-10) = -909, f(-2) = -19, f(3) = 36, f(10) = 609. Identify absolute minimum (x, y) = (-2, -19) and absolute maximum (x, y) = (10, 609).
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Let B = {b, b2.b3} be a basis for vector space V. Let T:V+ V be a linear transformation with the following properties. T(61) = 7b, -3b2. T(62) = b; -5b2. T(63) = -2b2 Find [T). the matrix for T relative to B. ITIB
Answer: since [B]^-1[B] = I.
Step-by-step explanation:
To find the matrix for T relative to B, we need to find the coordinates of the vectors T(b), T(b^2), and T(b^3) with respect to the basis B.
We have:
T(b) = 6T(b^2) + 1T(b^3) = b, -5b^2
T(b^2) = 1T(b^2) + 0T(b^3) = 7b, -3b^2
T(b^3) = 0T(b^2) - 2T(b^3) = 0, 4b^2
To find the matrix [T], we write the coordinates of T(b), T(b^2), and T(b^3) as columns:
[T] = [b, 7b, 0; -5b^2, -3b^2, 4b^2]
To check this matrix, we can apply it to the basis vectors and see if we get the same coordinates as the vectors T(b), T(b^2), and T(b^3):
[T][b] = [b, 7b, 0][1; 0; 0] = [b; -5b^2]
[T][b^2] = [b, 7b, 0][0; 1; 0] = [7b; -3b^2]
[T][b^3] = [b, 7b, 0][0; 0; 1] = [0; 4b^2]
These are the same as the coordinates we found for T(b), T(b^2), and T(b^3), so our matrix [T] is correct.
To find ITIB, we first need to find the inverse of the matrix [B] whose columns are the basis vectors b, b^2, and b^3. We can do this by row reducing the augmented matrix [B | I]:
[1 0 0 | 1 0 0]
[0 1 0 | 0 1 0]
[0 0 1 | 0 0 1]
So [B] is already in reduced row echelon form, and its inverse is just I:
[B]^-1 = [1 0 0; 0 1 0; 0 0 1]
Therefore,
ITIB = [B]^-1[T][B] = [T]
since [B]^-1[B] = I.
Two dice are thrown simultaneously. Find the probability of getting: (a) an even number as the sum; (b) a total of at least 10; (c) same number on both dice i.e. a doublet; (d) a multiple of 3 as the sum.
The probabilities are given as follows:
(a) an even number as the sum: 1/2.
(b) a total of at least 10: 1/6.
(c) same number on both dice i.e. a doublet: 1/6.
(d) a multiple of 3 as the sum: 1/3.
How to calculate a probability?A probability is calculated as the division of the desired number of outcomes by the total number of outcomes in the context of a problem/experiment.
The 36 total outcomes when a pair of dice are thrown are given as follows:
(1,1), (1,2), (1,3), (1,4), (1,5), (1,6)(2,1), (2,2), (2,3), (2,4), (2,5), (2,6)(3,1), (3,2), (3,3), (3,4), (3,5), (3,6)(4,1), (4,2), (4,3), (4,4), (4,5), (4,6)(5,1), (5,2), (5,3), (5,4), (5,5), (5,6)(6,1), (6,2), (6,3), (6,4), (6,5), (6,6)The sum follows the pattern even, odd, ..., even, so there are 18 even sums and 18 odd sums, hence the probability of an even sum is given as follows:
p = 18/36 = 1/2.
There are six outcomes with a sum of at least 10, hence the probability is of:
p = 6/36 = 1/6.
There are six doblets, (1,1), (2,2), ..., (6,6), ..., hence the probability is given as follows:
p = 6/36 = 1/6.
There are 12 outcomes in which the sum is a multiple of 3, hence the probability is given as follows:
p = 12/36
p = 1/3.
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Jonathan is looking to buy a car and the he qualified for a 7-year loan from a bank offering an annual interest rate of 3.9%, compounded monthly Using the formula below, determine the maximum amount Jonathan can borrow, to the nearest dollar, if the highest monthly payment he can afford is $300
Given the equation for the Total of Sum of Squares, solve for the Sum of Squares Due to Error.
SST=SSR+SSE
Select the correct answer below:
SSE=SST+SSR
SSE=SST−SSR
SSE=SSR−SST
For the equation of Total of Sum of Squares, the correct equation for Sum of Squares Due to Error is Option (b): SSE=SST−SSR.
What is an equation?
A mathematical definition of an equation is a claim that two expressions are equal when they are joined by the equals sign ("=").
In the equation SST = SSR + SSE, SST represents the total sum of squares, SSR represents the sum of squares due to regression, and SSE represents the sum of squares due to error.
To solve for SSE, we can rearrange the equation to get SSE = SST - SSR.
This means that the sum of squares due to error is equal to the total sum of squares minus the sum of squares due to regression.
In other words, SSE represents the variation in the data that cannot be explained by the regression model, while SSR represents the variation that can be explained by the regression model.
Therefore, the correct option is SSE = SST - SSR.
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Find a general solution for the differential equation y^(4) + 8y" – 9y = 0.
The general solution for the differential equation y^(4) + 8y" – 9y = 0 is y(x) = C1 * e^(1x) + C2 * e^(-1x) + C3 * e^(3ix) + C4 * e^(-3ix).
To find a general solution for the differential equation y^(4) + 8y" - 9y = 0, we will use the following terms: characteristic equation, auxiliary equation, and general solution.
Step 1: Write the characteristic (auxiliary) equation.
Replace the derivatives with powers of 'r' and set the equation equal to zero:
r^4 + 8r^2 - 9 = 0.
Step 2: Solve the characteristic equation.
This is a quadratic equation in r^2. Let's substitute x = r^2:
x^2 + 8x - 9 = 0.
Now, solve for x:
(x - 1)(x + 9) = 0.
The solutions for x are x1 = 1 and x2 = -9.
Step 3: Find the solutions for 'r'.
Since x = r^2, we can find the solutions for 'r':
r1 = sqrt(1) = 1,
r2 = -sqrt(1) = -1,
r3 = sqrt(-9) = 3i,
r4 = -sqrt(-9) = -3i.
Step 4: Write the general solution.
Now, using the values of 'r' that we found, we can write the general solution:
y(x) = C1 * e^(1x) + C2 * e^(-1x) + C3 * e^(3ix) + C4 * e^(-3ix).
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what proportion of a normal distribution is located in the tail beyond z = -1.00?
Hi, the proportion of a normal distribution located in the tail beyond z = -1.00 is approximately 0.3413 or 34.13%.
To find the proportion of a normal distribution located in the tail beyond z = -1.00, we will use the standard normal distribution table or a calculator with a z-table function.
Step 1: Identify the z-score. In this case, the z-score is -1.00.
Step 2: Use a calculator to look up the proportion in the standard normal distribution table. Using a z-table, we find that the proportion of the normal distribution up to z = -1.00 is 0.1587.
Step 3: Calculate the proportion in the tail.
Since the tail beyond z = -1.00 is to the left of this point, we need to calculate the remaining proportion.
To do this, subtract the proportion found in Step 2 from 0.5 (as half of the normal distribution is to the left of the mean, and the other half is to the right).
0.5 - 0.1587 = 0.3413
Therefore the answer is 0.3413 or 34.13%.
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assume that the random variable x is normally distributed, with mean =80 and a standard deviation =12. compute the probability p(x>95).
The probability P(X > 95) for a normally distributed random variable X is approximately 0.211.
How to compute the probability?To compute the probability P(X > 95) for a normally distributed random variable X with a mean of 80 and a standard deviation of 12, follow these steps:
1. Convert the raw score (95) to a z-score using the formula:
z = (x - mean) / standard deviation
z = (95 - 80) / 12
z ≈ 1.25
2. Use a standard normal distribution table or a calculator to find the area to the right of the z-score, which represents P(X > 95).
For z ≈ 1.25, the area to the right is ≈ 0.211
So, the probability P(X > 95) for a normally distributed random variable X with a mean of 80 and a standard deviation of 12 is approximately 0.211.
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simplify (-8)÷(-1÷4)÷(16)
Answer:
2
Step-by-step explanation:
(-8)÷(-1÷4) = 32
32/16 = 2
Answer:
(-8)÷(-0.25)÷(16)
Step-by-step explanation:
Suppose that a family wants to fence in an area of their yard for a vegetable garden to keep out deer. One side is already fenced from the neighbor's pro X x Part: 0/2 Part 1 of 2 (a) If the family has enough money to buy 140 ft of fencing, what dimensions would produce the maximum area for the garden? The dimensions that would produce the maximum area for the garden are 70 ft by 35 ft. $ Part: 1 / 2 Part 2 of 2 (b) What is the maximum area? The maximum area of the garden is ft? Х $
The dimensions of the garden, when the family has enough money to buy 140 ft of fencing, is 70 ft by 35 ft and the area is 2450 sq. ft.
To find the dimensions that would produce the maximum area for the garden, we need to use the concept of optimization.
Let's assume that the family wants to fence in a rectangular area of their yard for the vegetable garden.
Since one side is already fenced from the neighbor's property, we only need to fence the other three sides. Let's call the length of the garden x and the width y. Therefore, the perimeter of the garden would be P = x + 2y.
We know that the family has enough money to buy 140 ft of fencing, so we can set up an equation:
x + 2y = 140
Solving for x, we get:
x = 140 - 2y
To find the maximum area, we need to maximize the equation A = xy.
Substituting the value of x from the above equation, we get:
A = (140 - 2y)y
Expanding the equation, we get:
A = 140y - 2y²
To find the maximum area, we need to find the value of y that maximizes the equation. We can do this by taking the derivative of the equation with respect to y and setting it equal to zero:
dA/dy = 140 - 4y = 0
Solving for y, we get:
y = 35
Substituting this value of y back into the equation for x, we get:
x = 140 - 2(35) = 70
Therefore, the dimensions that would produce the maximum area for the garden are 70 ft by 35 ft.
To find the maximum area, we can substitute these values back into the equation for A:
A = (70)(35) = 2450 sq. ft.
Therefore, the maximum area of the garden is 2450 sq. ft.
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consider a binomial probability distribution with p = 0.35 and n = 8. determine the following probabilities: a. exactly three successes b. fewer than three successes c. six or more successes
The final expression of a binomial probability distribution is:
(a) P(X = 3) ≈ 0.2096
(b) P(X < 3) ≈ 0.4377
(c) P(X ≥ 6) ≈ 0.0739
How to finding probabilities in a binomial probability distribution?We can use the binomial probability formula to find the probabilities:
P(X = k) = (n choose k) * [tex]p^k[/tex]* [tex](1-p)^{(n-k)}[/tex]
where n is the number of trials, p is the probability of success, X is the random variable representing the number of successes,
and k is the number of successes we are interested in.
(a) P(X = 3) = (8 choose 3) * 0.35³ * 0.65⁵ ≈ 0.2096
(b) P(X < 3) = P(X = 0) + P(X = 1) + P(X = 2)
= (8 choose 0) * 0.35⁰* 0.65⁸ + (8 choose 1) * 0.35¹ * 0.65⁷ + (8 choose 2) * 0.35² * 0.65⁶
≈ 0.4377
(c) P(X ≥ 6) = P(X = 6) + P(X = 7) + P(X = 8)
= (8 choose 6) * 0.35⁶ * 0.65² + (8 choose 7) * 0.35⁷ * 0.65¹ + (8 choose 8) * 0.35⁸ * 0.65⁰
≈ 0.0739
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find the volume of the solid enclosed by the paraboloids z=16(x2 y2) and z=18−16(x2 y2).
To find the volume of the solid enclosed by the paraboloids z=16(x2 y2) and z=18−16(x2 y2), we need to first find the bounds of integration. Since the two paraboloids intersect at z=16, we can set z=16 and solve for x and y in terms of z:
16 = 16(x^2 y^2) -> x^2 y^2 = 1
1 = x^2 y^2 -> x = ±1 and y = ±1
So the bounds of integration are -1 ≤ x ≤ 1 and -1 ≤ y ≤ 1.
Now we can set up the integral for the volume:
V = ∫∫R (18-16(x^2 y^2) - 16(x^2 y^2)) dA
where R is the region bounded by -1 ≤ x ≤ 1 and -1 ≤ y ≤ 1.
Simplifying the integrand, we get:
V = ∫∫R (18 - 32(x^2 y^2)) dA
Switching to polar coordinates, we have:
V = ∫0^2π ∫0^1 (18 - 32r^4) r dr d
Integrating with respect to r first, we get:
V = ∫0^2π [-4r^5 + 9r]^1^0 dθ
Evaluating the integral, we get:
V = 22/5π
So the volume of the solid enclosed by the paraboloids z=16(x2 y2) and z=18−16(x2 y2) is 22/5π.
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let y be a continuous random variable with mean 11 and variance 9. using tcheby- shev’s inequality, find (a) a lower bound for p(6
The lower bound for y to be continuous random variable with mean 11 and variance 9 using Chebyshev's Inequality is 0.6413 or 64.13%.
Using the given information, we can apply Chebyshev's Inequality to find a lower bound for the probability P(6 ≤ y ≤ 16).
Given that y is a continuous random variable with a mean (μ) of 11 and a variance (σ²2) of 9, we have a standard deviation (σ) of 3.
Chebyshev's Inequality states that the probability of a random variable y being within k standard deviations of the mean is at least:
P(|y - μ| ≤ kσ) ≥ 1 - 1/k²
For this problem, we want to find the lower bound for P(6 ≤ y ≤ 16). We can rewrite this as:
P(11 - 5 ≤ y ≤ 11 + 5)
This means that we're interested in the probability of y being within 5 units of the mean, which is approximately 1.67 standard deviations (5/3 = 1.67). Therefore, k = 1.67.
Applying Chebyshev's Inequality:
P(|y - 11| ≤ 1.67 * 3) ≥ 1 - 1/(1.67²)
P(6 ≤ y ≤ 16) ≥ 1 - 1/(2.7889)
P(6 ≤ y ≤ 16) ≥ 0.6413
So, the lower bound for the probability P(6 ≤ y ≤ 16) is approximately 0.6413 or 64.13%.
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The lower bound for y to be continuous random variable with mean 11 and variance 9 using Chebyshev's Inequality is 0.6413 or 64.13%.
Using the given information, we can apply Chebyshev's Inequality to find a lower bound for the probability P(6 ≤ y ≤ 16).
Given that y is a continuous random variable with a mean (μ) of 11 and a variance (σ²2) of 9, we have a standard deviation (σ) of 3.
Chebyshev's Inequality states that the probability of a random variable y being within k standard deviations of the mean is at least:
P(|y - μ| ≤ kσ) ≥ 1 - 1/k²
For this problem, we want to find the lower bound for P(6 ≤ y ≤ 16). We can rewrite this as:
P(11 - 5 ≤ y ≤ 11 + 5)
This means that we're interested in the probability of y being within 5 units of the mean, which is approximately 1.67 standard deviations (5/3 = 1.67). Therefore, k = 1.67.
Applying Chebyshev's Inequality:
P(|y - 11| ≤ 1.67 * 3) ≥ 1 - 1/(1.67²)
P(6 ≤ y ≤ 16) ≥ 1 - 1/(2.7889)
P(6 ≤ y ≤ 16) ≥ 0.6413
So, the lower bound for the probability P(6 ≤ y ≤ 16) is approximately 0.6413 or 64.13%.
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The relationship between the number of pound (lb) of beef and the total cost in dollars shown in the graph. What is the unit price of beef?
1 lb/$5
$5/1lb
$1/5lb
$10/2lb
Answer:
Answer Choice B
Step-by-step explanation:
It is 5$ for 1 lb so that means you get the fraction $5/1lb
Breathing rates, in breaths per minute, were measured for a group of 10 subjects at rest, and then during moderate exercise. The results were as follows:
Subject Rest Exercise
1 15 27
2 16 37
3 21 39
4 17 37
5 18 40
6 15 39
7 19 34
8 21 40
9 18 38
10 14 34
Let μXμX represent the population mean during exercise and let μYμY represent the population mean at rest. Find a 95% confidence interval for the difference μD=μX−μYμD=μX−μY. Round the answers to three decimal places.
The 95% confidence interval is (, ).
The 95% confidence interval for the population mean difference in breathing rates between exercise and rest is (8.053, 20.147).
First, we need to find the sample mean and standard deviation for the difference in breathing rates between exercise and rest:
[tex]$\bar{d} = \frac{1}{n}\sum_{i=1}^{n}(d_i) = \frac{1}{10}\sum_{i=1}^{10}(x_i-y_i) = \frac{1}{10}(12+21+18+20+22+24+15+19+20+(-20)) = 14.1$[/tex]
Next, we need to find the t-value for a 95% confidence interval with 9 degrees of freedom. Using a t-distribution table, we find the t-value to be 2.306.
The margin of error for the 95% confidence interval is:
[tex]$ME = t_{0.025,9} \times \frac{s_d}{\sqrt{n}} = 2.306 \times \frac{9.081}{\sqrt{10}} = 6.047$[/tex]
Finally, we can construct the confidence interval for the population mean difference:
[tex]$(\bar{d} - ME, \bar{d} + ME) = (14.1 - 6.047, 14.1 + 6.047) = (8.053, 20.147)$[/tex]
Therefore, the 95% confidence interval for the population mean difference in breathing rates between exercise and rest is (8.053, 20.147).
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The given vectors form a basis for a subspace W of R3. Apply the Gram-Schmidt Process to obtain an orthogonal basis for W. (Use the Gram-Schmidt Process found here to calculate your answer.) -3 x3 0 sqrt(2y2sqrt(6y6 sqrt(2)266 sqrt(6)/3
The orthogonal basis for the subspace W is { -1, (0, sqrt(2y^2) + sqrt(6y^6))/(3sqrt(2y^2 + 6y^6)), (sqrt(2)y^2 + (sqrt(2)sqrt(6)y^6)/(3sqrt(2y^2 + 6y^6)), sqrt(2)sqrt(6)y^6 - (sqrt(2)sqrt(6)y^6)/(3sqrt(2y^2 + 6y^6)), sqrt(2/6))/sqrt(2y^4 + 12y^12 + 1/3) }.
To apply the Gram-Schmidt Process to the given vectors, we will first normalize each vector to obtain a unit vector. Then, we will subtract the projection of each subsequent vector onto the previous vectors to obtain orthogonal vectors. Finally, we will normalize the orthogonal vectors to obtain an orthogonal basis for the subspace W.
Let's begin:
1. Normalize the first vector -3:
[tex]v1 = (-3)/sqrt((-3)^2) = (-3)/3 = -1[/tex]
2. Normalize the second vector (0, sqrt(2y^2), sqrt(6y^6)):
[tex]v2 = (0, sqrt(2y^2), sqrt(6y^6))/sqrt(0^2 + (sqrt(2y^2))^2 + (sqrt(6y^6))^2)[/tex]
[tex]v2 = (0, sqrt(2y^2), sqrt(6y^6))/sqrt(2y^2 + 6y^6)[/tex]
3. Subtract the projection of v2 onto v1:
proj_v2_v1 = ((v2 . v1)/(v1 . v1)) * v1
where . represents the dot product
v2_orth = v2 - proj_v2_v1
v2_orth = (0, sqrt(2y^2), sqrt(6y^6))/sqrt(2y^2 + 6y^6) - ((0 + sqrt(2y^2) + sqrt(6y^6))(-1/3))(-1)
v2_orth = (0, sqrt(2y^2), sqrt(6y^6))/sqrt(2y^2 + 6y^6) + (sqrt(2y^2) + sqrt(6y^6))/3
4. Normalize the orthogonal vector v2_orth:
u2 = v2_orth/|v2_orth| = (0, sqrt(2y^2) + sqrt(6y^6))/(3sqrt(2y^2 + 6y^6))
5. Normalize the third vector (sqrt(2)y^2, sqrt(2)sqrt(6)y^6, sqrt(2/6)):
v3 = (sqrt(2)y^2, sqrt(2)sqrt(6)y^6, sqrt(2/6))/sqrt((sqrt(2)y^2)^2 + (sqrt(2)sqrt(6)y^6)^2 + (sqrt(2/6))^2)
v3 = (sqrt(2)y^2, sqrt(2)sqrt(6)y^6, sqrt(2/6))/sqrt(2y^4 + 12y^12 + 1/3)
6. Subtract the projection of v3 onto v1 and v2:
proj_v3_v1 = ((v3 . v1)/(v1 . v1)) * v1
proj_v3_v2 = ((v3 . u2)/(u2 . u2)) * u2
v3_orth = v3 - proj_v3_v1 - proj_v3_v2
v3_orth = (sqrt(2)y^2, sqrt(2)sqrt(6)y^6, sqrt(2/6))/sqrt(2y^4 + 12y^12 + 1/3) - (sqrt(2)y^2)(-1) - ((sqrt(2)sqrt(6)y^6)/(3sqrt(2y^2 + 6y^6)))(sqrt(2) + sqrt(6))
v3_orth = (sqrt(2)y^2 + (sqrt(2)sqrt(6)y^6)/(3sqrt(2y^2 + 6y^6)), sqrt(2)sqrt(6)y^6 - (sqrt(2)sqrt(6)y^6)/(3sqrt(2y^2 + 6y^6)), sqrt(2/6))/sqrt(2y^4 + 12y^12 + 1/3)
7. Normalize the orthogonal vector v3_orth:
u3 = v3_orth/|v3_orth| = (sqrt(2)y^2 + (sqrt(2)sqrt(6)y^6)/(3sqrt(2y^2 + 6y^6)), sqrt(2)sqrt(6)y^6 - (sqrt(2)sqrt(6)y^6)/(3sqrt(2y^2 + 6y^6)), sqrt(2/6))/sqrt(2y^4 + 12y^12 + 1/3)
Therefore, the orthogonal basis for the subspace W is { -1, (0, sqrt(2y^2) + sqrt(6y^6))/(3sqrt(2y^2 + 6y^6)), (sqrt(2)y^2 + (sqrt(2)sqrt(6)y^6)/(3sqrt(2y^2 + 6y^6)), sqrt(2)sqrt(6)y^6 - (sqrt(2)sqrt(6)y^6)/(3sqrt(2y^2 + 6y^6)), sqrt(2/6))/sqrt(2y^4 + 12y^12 + 1/3) }.
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20. Pluem, Frank, and Nanon are brothers, each with some money to give to their siblings. Pluem gives
money to Frank and Nanon to double the money they both have. Frank then gives money to Pluem and
Nanon to double the money they both have. Finally, Nanon gives money to Pluem and Frank to double
their amounts. If Nanon had 20 dollars at the beginning and 20 dollars at the end, how much, in dollars,
did the siblings have in total?
SOLUTION.
Let's start by using variables to represent the amount of money each sibling has at the beginning:
Let P be the amount of money Pluem has at the beginning.
Let F be the amount of money Frank has at the beginning.
Let N be the amount of money Nanon has at the beginning.
After Pluem gives money to Frank and Nanon to double their amounts, Frank will have 2F + P and Nanon will have 2N + P.
After Frank gives money to Pluem and Nanon to double their amounts, Pluem will have 2P + 2F + N and Nanon will have 2N + 2F + P.
Finally, after Nanon gives money to Pluem and Frank to double their amounts, Pluem will have 4P + 2F + 2N, Frank will have 4F + 2P + 2N, and Nanon will have 20 dollars.
We know that Nanon gave money to Pluem and Frank to double their amounts, so we can set up the equation:
4P + 2F + 2N = 2(2P + 2F + N) + 2(2F + 2P + N)
Simplifying this equation gives us:
4P + 2F + 2N = 8P + 8F + 4N
2P - 6F + 1N = 0
We also know that Nanon had 20 dollars at the beginning and at the end, so we can set up another equation:
2N + 2F + P = 40
Now we have two equations with three variables, which means we can't solve for all three variables. However, we can use the second equation to eliminate one variable and solve for the other two:
2N + 2F + P = 40
2P - 6F + N = 0
Solving for P in the second equation gives us:
P = 3F - 0.5N
Substituting this expression for P into the first equation gives us:
2N + 2F + (3F - 0.5N) = 40
Simplifying this equation gives us:
5F + N = 40
We know that Nanon had 20 dollars at the beginning, so we can substitute N = 20 into this equation:
5F + 20 = 40
Solving for F gives us:
F = 4
Substituting F = 4 into the equation 5F + N = 40 gives us:
N = 20
And substituting both F = 4 and N = 20 into the expression for P gives us:
P = 3F - 0.5N = 10
Therefore, Pluem had 10 dollars at the beginning, Frank had 4 dollars at the beginning, and Nanon had 20 dollars at the beginning. After the money exchanges, Pluem had 28 dollars, Frank had 28 dollars, and Nanon had 20 dollars. So the siblings had a total of 76 dollars.
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Calculate y(s) for the initial value problem y''-2y' y=cos(5t)-sin(5t), y(0)=1, y'(0)=1
To solve this initial value problem, we can use Laplace transforms. First, we take the Laplace transform of both sides of the differential equation:
s^2 Y(s) - s y(0) - y'(0) - 2[s Y(s) - y(0)] Y(s) = (s/(s^2 + 25)) - (5/(s^2 + 25))
To find y(t), we need to take the inverse Laplace transform of Y(s). This can be done using partial fractions:
Y(s) = (s + 4)/(s - 5)(s^2 + 7s + 25)
Y(s) = A/(s - 5) + (Bs + C)/(s^2 + 7s + 25)
Multiplying both sides by the denominator and equating coefficients, we get:
A(s^2 + 7s + 25) + (Bs + C)(s - 5) = s + 4
Solving for A, B, and C, we get:
A = -0.04, B = 0.16 and C = 0.12
Therefore, the inverse Laplace transform of Y(s) is:
y(t) = (-0.04e^5t + 0.16cos(5t) + 0.12sin(5t))u(t)
where u(t) is the unit step function. Thus, the solution to the initial value problem is:
y(t) = (-0.04e^5t + 0.16cos(5t) + 0.12sin(5t))u(t) + 1
To solve the given initial value problem, y'' - 2y' = cos(5t) - sin(5t), with initial conditions y(0) = 1 and y'(0) = 1, we will use the Laplace transform method.
1. Apply the Laplace transform to the entire equation:
L{y''} - 2L{y'} = L{cos(5t) - sin(5t)}
2. Use the properties of the Laplace transform:
s^2Y(s) - sy(0) - y'(0) - 2[sY(s) - y(0)] = (s/(s^2 + 25)) - (5/(s^2 + 25))
3. Substitute the initial conditions y(0) = 1 and y'(0) = 1:
s^2Y(s) - s - 1 - 2[sY(s) - 1] = (s/(s^2 + 25)) - (5/(s^2 + 25))
4. Solve for Y(s):
Y(s) = (s^2 + 2s + 1)/[(s^2 + 25)(s - 1)]
5. Apply the inverse Laplace transform to find y(t):
y(t) = L^{-1}{(s^2 + 2s + 1)/[(s^2 + 25)(s - 1)]}
This final expression represents the solution to the initial value problem. To obtain an explicit form of y(t), one would need to apply inverse Laplace transform techniques, such as partial fraction decomposition and using the inverse Laplace transform for each term.
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Select the correct hypotheses to investigate our research question: Has the distribution of beliefs changed since 2009?
a. H0: There is no association between beliefs and year. | HA: There is some association between beliefs and year.
b. H0: p1 = 0.32, p2 = 0.15, p3 = 0.46, p4 = 0.07 | HA: At least one pi differs from the proportions in 2009.
The correct hypothesis to investigate our research question: Has the distribution of beliefs changed since 2009 is
b. H0: p1 = 0.32, p2 = 0.15, p3 = 0.46, p4 = 0.07 | HA: At least one pi differs from the proportions in 2009. So the correct option is option b.
To investigate the about the correct hypotheses to investigate our research question and has the distribution of beliefs changed since 2009 select the following hypotheses:
H0: p1 = 0.32, p2 = 0.15, p3 = 0.46, p4 = 0.07 (There is no change in the distribution of beliefs since 2009.)
HA: At least one pi differs from the proportions in 2009 (There is some change in the distribution of beliefs since 2009.)
This is option (b) in your given choices. These hypotheses will allow you to test whether the distribution of beliefs has changed since 2009 by comparing the proportions of each belief in your sample to the proportions in 2009.
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Tony works as a Mexican Sign Language interpreter. When
someone speaks Spanish to a deaf person, he uses sign
language to communicate what that person is saying and he
also communicates the deaf person's response.
Tony works 4 hours each workday. He worked 12 hours last
week and 28 hours this week. Tony writes the expression 12 +
28 to represent the total hours he worked for both weeks.
Which equivalent expression could represent the total
number of hours worked in relation to the number of days
worked each week?
O 2(6+14)
O 4(3+7)
O 2(6+7)
O 4(3+28)
Answer:
4(3+7)
Step-by-step explanation:
The total number of hours Tony worked for both weeks is 12 + 28 = 40.
To find the equivalent expression that represents the total number of hours worked in relation to the number of days worked each week, we need to divide 40 by the total number of days worked, which is 10 (2 workdays per week).
So the expression we need is:
40/10 = 4(3+7)
Therefore, the answer is 4(3+7).