There are 40 students in a college statistics class. After the first exam, their instructor told them that the class scores were normally distributed with a 10 points mean of 76.9 and a standard deviation of 3.2. However, one of the students pointed out that the instructor recorded 28 for his score when he actually earned 82. The class recalculates the mean and standard deviation The mean is now 78.1. Which of the following is true about the standard deviation? A. The standard deviation will increase because the value of an exam score increased. B. The standard deviation will stay the same because it is not affected by a change in a single data value C. The standard deviation will decrease because the change moved an exam score closer to the mean

Answers

Answer 1

B. Because the standard deviation is unaffected by a change in a single data value, it will remain unchanged.

A change in a single data value has no impact on the standard deviation, which measures the spread of a data collection. As a result, even if the single data value changes, the standard deviation won't.

The variability of a data set is measured by the standard deviation. It is calculated by taking the square root of the average of the sum of the squares of the differences between each value in a data set and the mean. When a single value in a data set is changed, the mean of the data set will change, but the standard deviation will not be affected. This is because the standard deviation is not calculated based on individual data points, but on the overall variability of the data set. Therefore, when a single data value is changed, the standard deviation of the data set will remain the same.

Let x be one of the students in the class

Mean = (76.9 + 82)/2 = 79.4

Standard Deviation = sqrt(((76.9 - 79.4)^2 + (82 - 79.4)^2)/2) = 3.2

The complete question is : There are 40 students in a college statistics class. After the first exam, their instructor told them that the class scores were normally distributed with a 10 points mean of 76.9 and a standard deviation of 3.2. However, one of the students pointed out that the instructor recorded 28 for his score when he actually earned 82. The class recalculates the mean and standard deviation The mean is now 78.1. Which of the following is true about the standard deviation? A. The standard deviation will increase because the value of an exam score increased. B. The standard deviation will stay the same because it is not affected by a change in a single data value C. The standard deviation will decrease because the change moved an exam score closer to the mean D. The standard deviation will increase because the change moved an exam score further from the mean

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Related Questions

Find x in each triangle! Will award brainliest

Answers

Answer:

First triangle x=9

Second triangle x=20

Step-by-step explanation:

Using Pythagorean theorem

40^2+x=41^2

1600+x^2=1681

-1600        -1600

x^2=81

To find x we do the opposite of powers and find the squared

x=9

Second triangle

21^2+x^2=29^2

441+x^2=841

-441        -441

x^2=400

x=20

Suppose babies born after a gestation period of 32 to 35 weeks have a mean weight of 2500 grams and a standard deviation of 700 grams while babies born after a gestation period of 40 weeks have a mean weight of 3100 grams and a standard deviation of 390 grams. If a 34-week gestation period baby weighs 2950 grams and a 41-week gestation period baby weighs 3550 grams, find the corresponding z-scores. Which baby weighs more relative to the gestation period

Answers

Answer:

Z-score for 34-week baby = 0.643

Z-score for 41-week baby = 1.154

Baby weight of 41-week is more than the baby weight of 34-week in the gestation period.

Step-by-step explanation:

Given - Suppose babies born after a gestation period of 32 to 35 weeks have a mean weight of 2500 grams and a standard deviation of 700 grams while babies born after a gestation period of 40 weeks have a mean weight of 3100 grams and a standard deviation of 390 grams. If a 34-week gestation period baby weighs 2950 grams and a 41-week gestation period baby weighs 3550 grams

To find - Find the corresponding z-scores. Which baby weighs more relative to the gestation period.

Proof -

Given that,

In between period of 32 to 35 weeks

Mean = 2500

Standard deviation = 700

In between after a period of 40 weeks

Mean = 3100

Standard deviation = 390

Now,

For a 34-week baby,

X = 2950

For a 41-week baby,

X = 3550

Now,

Z-score = (X - mean) / Standard deviation

Now,

For a 34-week baby,

Z - score = (2950 - 2500) / 700 = 0.643

For a 41-week baby,

Z-score = (3550 - 3100) / 390 = 1.154

∴ we get

Z-score for 34-week baby = 0.643

Z-score for 41-week baby = 1.154

As 1.154 > 0.643

So,

Baby weight of 41-week is more than baby weight of 34-week in the gestation period.

Is this correct? Or are the numbers wrong

Answers

Answer:

I think that's right. But the angle in the corner actually might be the 28 degrees. One sec this question is a little confusing

Step-by-step explanation:

find number of A intersection B? help me plz​

Answers

Try this option:

1. to calculate the difference of the final sequence:

the difference between two terms of the sequence A is 4 (7-3=11-7=...=4) and the difference between two terms of the sequence B is 7 (9-2=16-9=...-7). It means, in the final sequence the difference should be 7*4=28;

2. to calculate the first term of the final sequence:

A={3;7;11;15;19;23;27;31;...;407} and B{2;9;16;23;30;...;709}. It means, the first term of the final sequence is 23.

3. to calculate the last term of the final sequence:

if 407<709, it means the last term is less than 407, then it is possible to make up the equation 23+28*n<407, where 23 - the 1st term of the final sequence, 28 - the difference of the final sequence, (n+1) - number of the last term of the final sequence and n∈Z.

n<(407-23)/28; n<13.71. If n∈Z, then n=13.

So, the last term of the final sequence is 23+28*13=387.

4. if the first term is 23, the last one is 387 and the difference of the final sequence is 28, then the final sequence is consists of 14 terms:

{23; 51; 79; 107; 135; 163; 191; 219; 247; 275; 303; 331; 359; 387}


The distance from Point C to the tower at Point A is 1.2 miles, while the distance from Point C to the tower at Point
Bis 1.8 miles. If mZACB=81", what is the distance, to the nearest tenth of a mile, between the water towers?

Answers

Since we are given with the three sides of the triangle and asked to determine the angle, we can use the cosine law.

What is the lateral area of the square pyramid, to the nearest whole number?
A. 165 m2
B. 176 m2
C. 330 m2
D. 351 m2

Answers

Answer:

1: A. 448 2: 209 pi cm^2 3: D. 351 m^2 4. B 240 cm^2 C. 561.1 cm^2

Step-by-step explanation:

just took the test!!!

Create a pattern with the rule n x3. Numbers 1 2 3 4 10

Answers

Answer:

10,13 and 16

Step-by-step explanation:

a company's stock was elling at $24 a share. A month later, it was selling at $30 a share. What percent is that gain

Answers

That would be a 25% gain

What’s the last equation

Answers

9514 1404 393

Answer:

  20 . . . . value of last equation

  (A, B, C) = (4, 5, 10) or (3 1/3, 6, 12) . . . . values of symbols

Step-by-step explanation:

If we call the symbols, in order of appearance, A, B, C, then the equations are ...

  2AB = 40   ⇒   AB = 20

  2C/B = 4   ⇒   C/B = 2

Multiplying the second equation by the first, we get ...

  (C/B)(AB) = AC = (2)(20) = 40   ⇒   AC = 40

Then the last equation is ...

  (C-B)A = __

  AC -AB = __ = 40 -20 = 20

The value of the last equation is 20.

_____

Per the above, we have AC = 40. The third equation is ...

  (C +3A) = 22

Using the first relation, we have A = 40/C, so the second becomes ...

  C +3(40/C) = 22

  C² -22C +120 = 0

  (C -10)(C -12) = 0

  C = 10 or 12

As you can see, there are two possible solutions for the values of the symbols. The corresponding values of the other variables are ...

  A = 40/C = 4 or 3 1/3

  B = 20/A = C/2 = 5 or 6

The values of the variables are ...

  (A, B, C) = (4, 5, 10) or (3 1/3, 6, 12)  

What is the inverse relation of f(x)=1/5x−4/5?
y=1/5x−4
y=−1/5x+5/4
y=−5x−4
y=5x+4

Answers

Answer:

[tex]y' = 5x + 4[/tex]

Step-by-step explanation:

Given

[tex]f(x) = \frac{1}{5}x - \frac{4}{5}[/tex]

Required

The inverse relation

[tex]f(x) = \frac{1}{5}x - \frac{4}{5}[/tex]

Rewrite as:

[tex]y = \frac{1}{5}x - \frac{4}{5}[/tex]

Swap x and y

[tex]x = \frac{1}{5}y - \frac{4}{5}[/tex]

Multiply through  by 5

[tex]5x = y - 4[/tex]

[tex]y = 5x +4[/tex]

Rewrite the new function as:

[tex]y' = 5x + 4[/tex]

Larry has a cylinder shaped pictures that is 13 inches long and radius of 4 inches. Sandra has a cylinder shaped pitcher that is 8 inches long and radius of 6 inches. The volume of Larry’s picture is approximately __. The volume of Sandra’s pitcher is approximately __?

Answers

The volume of Larry’s picture is approximately 653in³

The volume of Sandra’s pitcher is approximately 905in³

How to determine their volume

The formula for calculating the volume of a cylinder is expressed as;

V = πr²h

Such that the parameters are;

V is the volumer is the radiush is the height

Now, substitute the values, we have;

Larry's cylinder

Volume = 3.14 × 4² × 13

Find the square value and multiply the expression

Volume = 653in³

Sandra's cylinder

Volume = 3.14 × 6² × 8

Find the square value and multiply the expression

Volume = 905in³

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Which of the following equations represents a linear function

Answers

Answer:

its B

Step-by-step explanation:

please like my answer . brainliest please

How to figure out square feet of counter tops

Answers

Answer:

Chapter Three: Calculate Total Countertop Square Footage

To calculate the total square footage (after placing seams) you will need to follow this formula: “L” x “W” / 144 = s.f. (Length times width divided by 144 = square feet).

HELPPP PLEASE ANSWER

Answers

those answers bussin bussin 2 bad u cant have none

ZABD and ZDBC are supplementary angles.
What is the measure of x?
x = [?]°
7D
AK
126
x
B

Angles are not drawn to scale.
Enter

Answers

x=102°Answer:

x+78=180 supplementary angle

x=180-78=102

Help please will mark brainliest!!

Answers

Answer:

5,4 km

Step-by-step explanation:

we know the area and the width.

the formula of the area of a parallelogram is

A = length x width

if we substitute the values that we know, we have

23,1 = x * 4,3

to find x we have to divide the two members by 4,3

x = 23,3/4,3 = 5,4 km

Solve the following right triangle. Round to the nearest tenth.

Answers

You can try 110 if it’s not that then try 920

Given that these triangles are similar, what is the perimeter of triangle PQR? Show your work.

If someone could answer fr this time that would be great.

Answers

Answer:

24

Step-by-step explanation:

I use the Pythagoras theorem.

[tex]\sqrt{a^{2} +b^{2} } =c^{2}[/tex]

[tex]4^{2}{x}6^{2} = c^{2}[/tex]

16 x 36= 576

[tex]\sqrt{576} = 24[/tex]

What is the area of the triangle?

Answers

Answer:

The formula to find a triangle is (L+W)/2

Step-by-step explanation:

doivhrghfufvh - 10 points!

Answers

Answer:

I'm sure it's already all the way simplified since there are no common terms

I could he wrong but I dont think theres anything more you can do since they are all their own different term

Step-by-step explanation:

for example if it was 7x-2x-1 then you would subtract 7x and 2x and then it would come put to be 5x-1

hope this helped at all

Austin's paycheck showed a regular weekly salary of $385.50, a deduction of $16.35, a commission of $28.75, and $37.35 for overtime. Which equation correctly finds Austin's final pay?



-$385.50 + $16.35 + (-$28.75) + (-$37.35) = - $435.25


$385.50 + $16.35 + (-$28.75) + (-$37.35) = $355.75


$385.50 + (-$16.35) + $28.75 + $37.35 = $435.25


$385.50 + (-$16.35) + $28.75 + $37.35 = -$467.95

Answers

Answer:

Answer option c is correct.

Step-by-step explanation:

385.50 is adding to the amount because it his paycheck. 16.35 is subtracted because it is bing deducted. Then there is the adding amount of 28.75 and 37.35 because of his commission and overtime. When you add it all up, you get 435.25. This whole thing would look like this in equation format:

385.50 +(-16.35) + 28.75 + 37.35 = 435.25.

Tara had 1 5/8 pounds of dried nuts. She ate 1/4 pound of dried nuts each day for 6 days? How many pounds of dried nuts did Tara have left after 6 days?

Answers

Answer:

1/8

Step-by-step explanation:

its easy just count backwards by 2/8 each time

3. What is the value of x? A 52C 86 B 68 D 104

Answers

Answer:

86 i guess

Step-by-step explanation:

Solve sqare root of x-1= x-3. Check for extraneous solutions.
O A. No solution
O B. x = 2,5
C. X = 2
D. x = 5

Answers

No solution is the answer

A

Answer:x=2,5

Step-by-step explanation:

sqrtx-1=x-3. Sqrt5-1=5-3

sqrt2-1=2-3. Sqrt4=

sqrt1=1. 2=2

1=1

Alex has trained his puppy, Popper, to
jump through a ring. According to Alex's
measurements and calculations, the ring
has a diameter of 3.5 feet. What is the
ring's circumference (use 3.14 for pi)?

1. 8.75 ft

2. 11.32 ft

3. 12.25 ft

4. 10.99 ft

Answers

Answer:

4.10.99

Step-by-step explanation:

3.14 * 3.5

The number of subscribers to a web service is growing exponentially. If there were 100,000 subscribers initially and it grows by 2.4% per month, how many subscribers will there be after a year? Round your answer to the nearest whole number of subscribers.

Answers

Answer:

280,000

Step-by-step explanation:

Solve

Given: 100,000 subscribers increases by 2.4% per month

To find: After a year, how much will that be?

First step:

Find the increase of the subscribers per month

100,000 of 2.4%

Set up an equation

2.4/100 × 100,000/1

Cross multiply, cancel zeros in both 100,000 and 100. Which is equal to:

2.4/1 x 1,000/1 =

2,400

Second step: If it increases per month,

then to find the year, find out how many months is in a year:

12 months = 1 year

Now that has been figured out, multiply the result by the result in the first step:

12 × 2400 = 28.800

Therefore, the number of subscribers will be after a year

simplify the expression
[tex] \sqrt[3]{686x {}^{4} } y {}^{7} [/tex]

Answers

The expression can be simplified as  [tex]7x\sqrt[3]{ 2x} y^7[/tex].

What is an expression?

An expression in mathematics is made up of numbers, variables, and functions (such as addition, subtraction, multiplication or division, etc.)

A phrase in language may contain an action on its own, but it does not constitute a whole sentence.

Given:

The expression = [tex]\sqrt[3]{686x^4} y^7[/tex]

Factorize 686 we get 7³ × 2

= [tex]\sqrt[3]{7^3\times 2x^4} y^7[/tex]

= [tex]7x\sqrt[3]{ 2x} y^7[/tex]

Therefore, the expression can be simplified as  [tex]7x\sqrt[3]{ 2x} y^7[/tex].

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A factory begun producing new parts. Data were collected on the
number of defective parts per 10,000 parts produced. The graph
shown displays some of the data for the first 10 weeks of production.
Write an equation that best models the data?

Answers

The equation that best models the data is 10x + y = 160 if the number of defective parts per 10,000 parts produced and points (10, 60) and (9, 70)

What is a linear equation?

It is defined as the relation between two variables if we plot the graph of the linear equation we will get a straight line.

If in the linear equation one variable is present then the equation is known as the linear equation in one variable.

From the graph:

(10, 60) and (9, 70)

The line equation of best fit:

(y - 70) = (70-60)/(9-10)(x-9)

y - 70 = -10(x-9)

y - 70 = -10x + 90

10x + y = 160

Thus, the equation that best models the data is 10x + y = 160 if the number of defective parts per 10,000 parts produced and points (10, 60) and (9, 70)

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Solve for h -4(-6h - 7) = 9h + 10h - 7

Answers

Answer:

h=-7

Step-by-step explanation:

-4(-6h - 7) = 9h + 10h - 7

24h+28=19h-7

Both side -28

24h+28-28=19h-7-29

24h=19h-35

Both side -19h

24h-19h=19h-19h-35

5h=-35

h=-7

Answer:

h = -7

Step-by-step explanation:

-4(-6h-7)= 9h+ 10h-7

24h+ 28=19h-7

-19. -28. -19 -28

5h -35

h= -7

Round to the nearest hundredth 2^x =243

Answers

9514 1404 393

Answer:

  7.92

Step-by-step explanation:

The value of x can be found by taking logarithms.

  x·log(2) = log(243)

  x = log(243)/log(2)

  x ≈ 7.9248125...

  x ≈ 7.92

__

A graphing calculator offers a couple of different options for solving the problem.

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