The scores of students on the SAT college entrance examinations at a certain high school had a normal distribution with mean u and standard deviation o = 26.5. (a) What is the probability that a single student randomly chosen from all those taking the test scores 549 or higher? ANSWER: For parts (b) through (d), consider a simple random sample (SRS) of 30 students who took the test. (b) What are the mean and standard deviation of the sample mean score ł, of 30 students? The mean of the sampling distribution for ž is: The standard deviation of the sampling distribution for ž is: (c) What z-score corresponds to the mean score 7 of 549?

Answer:

how many brain cells do you have compared to the average person?

Step-by-step explanation:

(a)  Explanation:  In order to prove that X and Y are dependent random variables, we need to show that: pX,Y(x,y)≠pX(x)pY(y) when (x,y) ∈ T which means the joint probability of X and Y is not equal to the product of the marginal probability of X and Y.

For (x,y) ∈ T, pX,Y(x,y) = P (X=1, Y=y) = 1+y

But pX(x) = P(X=1) = Σ pX,Y(1, y) = Σ (1+y)

where the summation is taken over all y for which (1, y) ∈ T. For (1,1) ∈ T,

we get pX,Y(1,1) = 2 and pX(1) = Σ pX,Y(1,y) = 2 + 3 = 5. So, pX,Y(1,1) ≠ pX(1)pY(1) which implies that X and Y are dependent random variables.

(b) E[XY] = Σ Σ xy pX,Y(x,y) where the summation is taken over all x and y for which pX,Y(x,y) > 0.

Substituting the values, we get, E[XY] = Σ Σ xy (1+y) where the summation is taken over all (x,y) ∈ T.

So, E[XY] = (1+1) (1+1) + (1+2) (1+2) + (1+3) (1+3) = 2*2 + 3*4 + 4*6 = 2 + 12 + 24 = 38.

(c) Covariance of X and Y can be determined as follows: Cov(X,Y) = E(XY) - E(X)E(Y)Now, E(X) = Σ x pX(x) and E(Y) = Σ y pY(y)

Substituting the values, we get E(X) = 5/9 and E(Y) = 20/9

Therefore, Cov(X, Y) = E(XY) - E(X)E(Y) = 38 - (5/9) (20/9) = 38 - 100/81 = 998/81.

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Answer:  Gradpoint answer

C.

7

Step-by-step explanation:  Math.way answer

Move all terms to the left side and set equal to zero. Then set each factor equal to zero.

Exact Form:

z = 0 ,  7/ 4

Decimal Form:

z = 0 ,  1.75

Mixed Number Form:

z = 0 ,  1  3/ 4

Answer:

7

Step-by-step explanation:

(z – 4)(2z + 1) = z(2z + 1) – 4(2z + 1) = 2z2 + z – 8z – 4 = 2z2 – 7z – 4

The second term is –7z, so 7 fills in the blank.

Answer:

E Z

10

Step-by-step explanation:

15 = 1.5t

so t = 15/1.5

      = 10

Answer: t = 10

1. Switch sides

- 1.5t = 15

2. Multiply both sides by 10

- 15t = 150

3. Divide both sides by 15

4. Simplify

t = 10

Answer:

f = 6

Step-by-step explanation:

Plug in what you know then solve:

f = d + 1

f = 5 + 1

f = 6

Answer:

[tex]x=\frac{-(-2)\±\sqrt{(-2)^2-4(3)(0)} }{2(3)}[/tex]

Step-by-step explanation:

Quadratic formula: [tex]x=\frac{-b\±\sqrt{b^2-4ac} }{2a}[/tex] when the equation is [tex]0=ax^2+bx+c[/tex]

The given equation is [tex]1=-2x+3x^2+1[/tex]. Let's first arrange this so its format looks like [tex]y=ax^2+bx+c[/tex]:

[tex]1=-2x+3x^2+1[/tex]

[tex]1=3x^2-2x+1[/tex]

Subtract 1 from both sides of the equation

[tex]1-1=3x^2-2x+1-1\\0=3x^2-2x+0[/tex]

Now, we can easily identify 3 as a, -2 as b and 0 as c. Plug these into the quadratic formula:

[tex]x=\frac{-b\±\sqrt{b^2-4ac} }{2a}\\x=\frac{-(-2)\±\sqrt{(-2)^2-4(3)(0)} }{2(3)}[/tex]

I hope this helps!  

Answer:

C. 672

Step-by-step explanation:

Answer:

C) 672

Step-by-step explanation:

Answer:

Ты русский? на этом сайте только американцы они тебе не помогут ни чем

Step-by-step explanation:

Answer:

0.333333

Step-by-step explanation:

0.333 yards are in one foot

Answer: the answer is 56

Step-by-step explanation: since the f(x) is -7 it would be 9 times -7 then minus 7 and get the answer.

16^1/5 = 2^4/5 .. & .. 8^3/4 = 2^9/4

____________

2^4/5 × 2^x = 2^9/4

2^16/20 × 2^x = 2^45/20

2^[ ( 16/20 ) + x ] = 2^45/20

16/20 + x = 45/20

x = 45/20 - 16/20

x = 29/20

The standardized test statistic is 12.961

To test the claim that σ = 2.38.7 with n - 12, a = -0.05 and 52-32.4,

we need to calculate the standardized test statistic.

The appropriate response is 12.961.

So, the standardized test statistic is calculated as follows:

`x = (n - 1)s² / σ²`

Where `n` is the sample size, `s` is the sample standard deviation, and `σ` is the population standard deviation.

`n = 12, s = 52 - 32.4 = 19.6, and σ = 2.38.7`

Then, `x² = (12 - 1)(19.6)² / (2.38.7)² = 12.961`

Therefore, the appropriate response is 12.961`.

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There are 40,320 different ways the race with 8 runners can be completed.

To determine the number of different ways a race with 8 runners can be completed, we can use the concept of permutations.

In a race with no tie, the order in which the runners finish matters. We want to find the number of permutations of 8 runners.

The formula to calculate permutations is given by n!, where n represents the number of items being permuted.

In this case, there are 8 runners, so the number of different ways the race can be completed is:

8! = 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 = 40,320.

Each permutation represents a unique arrangement of the runners crossing the finish line. By considering the order of finish for each runner, we account for all possible outcomes in the race.

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Answer:

Step-by-step explanation:

Answer:

? is there a option?

Step-by-step explanation:

Answer:

37

Step-by-step explanation:

6x+7

6(5)+7

37

Answer:

x = 19.5   or 19 1/2

Step-by-step explanation:

cos 41 = 14.7/x

x = 19.5

Answer:

Step-by-step explanation:

99(v + 9) is all you need here.

Answer:

x < -2 ?

Step-by-step explanation:

A better approximation of f'(0) using Richardson's extrapolation is -6.91412.

To find a better approximation of f'(0) using Richardson's extrapolation, we can apply the formula:

[tex]R(1,1) = f'(h) + (f'(h) - f'(2h))/((1/2)^1 - 1)[/tex], where h is the step size.

Given the values:

f'(1) = -4.50557 (for h = 1)

f'(0.5) = -2.09702 (for h = 0.5)

Let's calculate R(1,1):

[tex]R(1,1) = f'(1) + (f'(1) - f'(0.5))/((1/2)^1 - 1)\\ = -4.50557 + (-4.50557 - (-2.09702))/(2 - 1)\\ = -4.50557 + (-2.40855)/1\\ = -4.50557 - 2.40855\\ = -6.91412.[/tex]

Therefore, a better approximation of f'(0) using Richardson's extrapolation is -6.91412.

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what inequality??????

(i) The uniform and normal distribution for chromium is 2.4927 and 16.5762. (ii) The uniform and normal distribution for Barium is 0.0031 and 0.3323. (iii) The uniform and normal distribution for Fluoride is 0.0289 and 0.0167

For each substance, the standard deviation o is estimated by assuming uniform distribution and normal distribution. The uniform distribution standard deviation is computed using the formula as follows:

o = (b-a) / √12

where

a is the minimum value,

b is the maximum value.

The normal distribution standard deviation is calculated using the formula as follows:

o = (b - a) / 6.

Estimate the standard deviation o for each substance. Round your answers to 4 decimal places. Substance Chromium Barium Fluoride Uniform Distribution. The range of contaminant levels for chromium is from 0.45 to 8.61. The minimum value is 0.45 and the maximum value is 8.61.

(i) Chromium

Uniform distribution

o = (b-a) / √12

  = (8.61 - 0.45) / √12

  = 2.4927

  ≈ 2.4927 (rounded to 4 decimal places)

Normal Distribution

The maximum value for chromium is 100 and the minimum value is 0.45. Thus, the standard deviation o for chromium using normal distribution is:

o = (b-a) / 6

  = (100 - 0.45) / 6

  = 16.5762

  ≈ 16.5762 (rounded to 4 decimal places)

(ii) Barium

Uniform Distribution

The range of contaminant levels for barium is from 0.006 to 0.018. The minimum value is 0.006 and the maximum value is 0.018.

Thus, the standard deviation o for barium using uniform distribution is:

o = (b-a) / √12

  = (0.018 - 0.006) / √12

  = 0.0031

  ≈ 0.0031 (rounded to 4 decimal places)

Normal Distribution

The maximum value for barium is 2 and the minimum value is 0.006. Thus, the standard deviation o for barium using normal distribution is:

o = (b-a) / 6

  = (2 - 0.006) / 6

  = 0.3323

  ≈ 0.3323 (rounded to 4 decimal places)

(iii) Fluoride

Uniform Distribution  

The range of contaminant levels for fluoride is from 1.04 to 1.14. The minimum value is 1.04 and the maximum value is 1.14. Thus, the standard deviation o for fluoride using uniform distribution is:

o = (b-a) / √12

  = (1.14 - 1.04) / √12

  = 0.0289

  ≈ 0.0289 (rounded to 4 decimal places)

Normal Distribution

The maximum value for fluoride is 1.14 and the minimum value is 1.04. Thus, the standard deviation o for fluoride using normal distribution is:

o = (b-a) / 6

  = (1.14 - 1.04) / 6

  = 0.0167

  ≈ 0.0167 (rounded to 4 decimal places).

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Complete Question:

The Environmental Protection Agency (EPA) requires that cities monitor over 80 contaminants in their drinking water. Samples from the Lake Huron Water Treatment Plant gave the results shown here. Only the range is reported, not the mean.

For each substance, estimate the standard deviation σ by using one of the methods shown in Table 8.11 in section 8.8. (Round your answers to 4 decimal places.)

(i) The uniform and normal distribution is Chromium.  

(ii) The uniform and normal distribution is Barium.  

(iii) The uniform and normal distribution is Fluoride.

Answer:

i believe your answer is.

4,789,658,950

Step-by-step explanation:

In a survey project, an outcome variable refers to the variable that represents the main focus or result of interest in the study.

In a survey project, the outcome variable, otherwise known as the dependent variable, represents the main focus or result of interest.

It is the variable researchers seek to measure or predict based on the collected data. The purpose of an outcome variable is to provide insights into the specific aspect being studied, enabling researchers to understand relationships between independent variables and the outcome.

Analyzing the outcome variable allows for drawing conclusions, identifying patterns, and determining the impact of various factors. It serves as a crucial metric for evaluating success, making informed decisions, and drawing meaningful conclusions from the survey findings.

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The proportion of the low-income group who are social networking users is approximately 0.6928, and the proportion of the high-income group who are social networking users is approximately 0.6464.

a) To find the proportions, we divide the number of social networking users in each income group by the total number of respondents in that group. For the low-income group, the proportion is 300/433 ≈ 0.6928. For the high-income group, the proportion is 353/546 ≈ 0.6464.

b) The difference in proportions is obtained by subtracting the proportion of the high-income group from the proportion of the low-income group. The difference is approximately 0.6928 - 0.6464 = 0.0464.

c) The standard error of the difference can be calculated using the formula SE = √[(p1(1-p1)/n1) + (p2(1-p2)/n2)], where p1 and p2 are the proportions of social networking users in each group, and n1 and n2 are the sample sizes of each group. Plugging in the values, we get SE ≈ √[(0.6928(1-0.6928)/433) + (0.6464(1-0.6464)/546)] ≈ 0.0348.

d) To construct a confidence interval for the difference between the proportions, we can use the formula CI = (difference ± critical value × SE). For a 99% confidence level, the critical value can be found using a standard normal distribution table, which is approximately 2.576. Plugging in the values, we get the 99% confidence interval ≈ (0.0464 ± 2.576 × 0.0348) ≈ (0.0464 ± 0.0685).

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Answer:

57%

Step-by-step explanation:

FORMULA:LESS/TOTAL × 100%

=52/92 × 100%

=56.52 %

ROUND OFF TO NEAREST WHOLE NUMBER

56.52%=57%

(because the 5 after the (.) is near 1)