2. Suppose over several years of offering AP Statistics, a high school finds that final exam scores are normally distributed with a mean of 78 and a standard deviation of 6. A. What are the mean, standard deviation, and shape of the distribution of x-bar for n

Answers

Answer 1

Answer:

By the Central Limit Theorem, the mean is 78, the standard deviation is [tex]s = \frac{6}{\sqrt{n}}[/tex] and the shape is approximately normal.

Step-by-step explanation:

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

Mean of 78 and a standard deviation of 6

This means that [tex]\mu = 78, \sigma = 6[/tex]

Samples of n:

This means that the standard deviation is:

[tex]s = \frac{\sigma}{\sqrt{n}} = \frac{6}{\sqrt{n}}[/tex]

What are the mean, standard deviation, and shape of the distribution of x-bar for n?

By the Central Limit Theorem, the mean is 78, the standard deviation is [tex]s = \frac{6}{\sqrt{n}}[/tex] and the shape is approximately normal.


Related Questions

A screening test for a disease shows a positive result in 91% of all cases when the disease is actually present and in 7% of all cases when it is not. Assume that the prevalence of the disease is 1 in 650. If the test is administered to a randomly chosen individual, what is the probability that the result is positive

Answers

Answer:

0.0713 = 7.13% probability that the result is positive.

Step-by-step explanation:

Probability of a positive test:

91% of 1/650(has the disease).

7% of 1 - 1/650 = 649/650(does not have the disease). So

[tex]p = 0.91\frac{1}{650} + 0.07\frac{649}{650} = \frac{0.91 + 0.07*649}{650} = 0.0713[/tex]

0.0713 = 7.13% probability that the result is positive.

) As an ice cube melts its surface area is decreasing at a rate of 6cm2/sec. Find the rate at which the length of each side is decreasing at the moment when each side has length 2 cm. [Hint: a cube has 6 sides and each side has area x 2 where x is the side length]

Answers

Answer:

The rate of decreasing of the length is 0.25 cm/s.

Step-by-step explanation:

The surface area of the ice cube is:

[tex]A_{ice}=6x^{2}[/tex]

Where x is the side of the cube.

Let's take the derivative of A with respect to "t" to get the rate of change.

[tex]\frac{dA_{ice}}{dt}=12x\frac{dx}{dt}[/tex]

We know that dA/dt = 6 cm²/s and x is 2 cm, so we just need to solve it for dx/dt which is the rate change of the length.

[tex]6=12(2)\frac{dx}{dt}[/tex]

[tex]\frac{dx}{dt}=\frac{1}{4}\: cm/s[/tex]

Therefore, the rate of decreasing of the length is 0.25 cm/s.

I hope it helps you!

Find the area of a regular polygon with 9 sides that has a side length of 12 inches and an apothem of 15 inches.​

Answers

Answer:

An apothem is a line drawn from the centerpoint of the polygon to one side of the polygon. There is a formula for area in terms of apothem:

A = (1/2)*(Perimeter)*(Apothem)

The perimeter of the regular polygon  is just the length of one side multiplied with the number of sides. Since a polygon with   9 sides,

P = 9(15) = 135in

A = 1/2 ×135 × 12

A = 810 square inches ans

Describe the relationship of the formula.
y = kx

Answers

If two variables (x and y) are directly proportional to each other, their relationship can be described as y=kx, where k is how they change relative to one another

This line is parallel to the line 2x + 6y = 12.

Answers

Answer:

y = 1/3x + 4 1/3

hope this helps

have a good day :)

Step-by-step explanation:

Answer:

[tex]6y = - 2x + 12 \\ 3y = - x + 6 \\ y = - \frac{1}{3} x + 2[/tex]

An observer in a blimp sights a football stadium at a certain angle of depression. If the blimp is at an altitude of 1600 ft and the horizontal distance between the blimp and stadium is 2372 ft. Determine the angle of depression from the blimp to the stadium to the nearest degree.

Answers

Answer:

http://maggieevans.weebly.com/uploads/8/3/6/6/8366984/unit_2_test_review_answers.pdf

Step-by-step explanation:

The link is there it might have some other answers scroll down on the page link. No this is not a scam i promise <3

Determine if the sequence below is arithmetic or geometric and determine the common difference / ratio in simplest form.
20, 15, 10

Answers

Answer:

a. T² - T¹ = d ( A. P) -5

b. T²/T¹ = r (G. P) 3/4

Step-by-step explanation:

a. 15 - 20 = -5

b. 15/20 = 3/4

Answer:

This is an arithmetic sequence and the common difference is equal to -5.

Need help fast please thanks

Answers

Answer:

c = 41 ft

Step-by-step explanation:

To solve this problem, we can use the pythagorean theorem, which is defined by the formula [tex]a^2+b^2=c^2[/tex]. We are given both the lengths of the legs, so all we need to do is to plug them both in and solve for c:

[tex]9^2+40^2 = c^2\\c^2 = 81 + 1600\\c^2 = 1681\\c = 41[/tex]

This is the first option.

Numerical Response
15b - 6 - 3b + 10
This polynomial simplifies to the form
nb + m
then n + m=?

Answers

Answer:

[tex]\huge\boxed{Answer\hookleftarrow}[/tex]

[tex]15b - 6 - 3b + 10 \\ 15b - 3b - 6 + 10 \\ = 12b + 4[/tex]

12b + 4 is in the form nb + m, where,

n = 12m = 4

So,

[tex] = n + m \\ = 12 + 4 \\ = 16[/tex]

16 is the correct answer.

ʰᵒᵖᵉ ⁱᵗ ʰᵉˡᵖˢ

# ꧁❣ RainbowSalt2²2² ࿐

X - 13 < -11 Does anyone know this

Answers

Answer:

x < 2

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to Right  

Equality Properties

Multiplication Property of Equality Division Property of Equality Addition Property of Equality Subtraction Property of Equality

Step-by-step explanation:

Step 1: Define

Identify

x - 13 < -11

Step 2: Solve for x

[Addition Property of Equality] Add 13 to both sides:                                    x < 2

Here we see that any value x smaller than 2 would work as a solution.

Last Question Plz Help

Answers

Answer:

this is good looking nice photo but li can't give you answer of that sorry.

Step-by-step e this https://www.commonlit.org/en/students/student_lesson_activities

will give more points if correct

Answers

The answer to that would be 0, 1, -1, and 6.
Have a good day:)

Answer:

REVENGE

Step-by-step explanation:

The average domestic economy car gets around 30.9 miles per gallon (MPG) with a standard deviation of 2.88. Suppose domestic manufacturers all vow to increase fuel economy over the next 2 years. If successesful, 2.9 is added to every observation in the dataset. What is the new mean

Answers

Answer:

33.8

Step-by-step explanation:

Given that :

Initial Average miles per gallon = 30.9

Uniform value added to each data in the set = 2.9

The mean value of a dataset shifts by the uniform value added to each value in the dataset. This is always true whenever a uniform value is added to values across a dataset irrespective of the number of samples.

Hence

Initial mean. + uniform Value

30.9 + 2.9 = 33.8

~Help please and ty~ ✨Brainilist✨

Answers

Answer:

-37

Step-by-step explanation:

-37/100 is rational.

Answer:

-37/100

Step-by-step explanation:

Hi plz help, if you can ill mark you 5 starz! :)

Answers

Answer:

Part A = A

Part B - 308

308 cubic feet


Hope you have a wonderful day

Express the area of the entire rectangle.
Your answer should be a polynomial in standard form.
X+7
X+1
Area=
ASAP!!!!!!

Answers

Answer:

Area = x² + 8x + 7

Step-by-step explanation:

Area of a rectangle formula = L * W

Length (L) of the given figure = (x + 7)

Width (W) of the given figure = (x + 1)

Area = L * W

Area = (x + 7) * (x + 1)

=> x * x = x²

=> x * 1 = 1x or x

=> 7 * x = 7x

=> 7 * 1 = 7

Combining it all together;

Area = x² + 1x + 7x + 7

Combine the like terms:

Area = x² + 8x + 7

Hope this helps!

The area of the entire rectangle in the polynomial form will be x² + 8x + 7.

What is the area of the rectangle?

Let W be the rectangle's width and L its length. The area of the rectangle is the multiplication of the two different sides of the rectangle. Then the rectangle's area will be given as,

Area of the rectangle = L × W square units

The dimensions of the big rectangle are x + 1 high and x + 7 long. Then the area of the rectangle is calculated as,

A = (x + 7)(x + 1)

Simplify the equation, then we have

A = (x + 7)(x + 1)

A = x² + 7x + x + 7

A = x² + 8x + 7

More about the area of the rectangle link is given below.

https://brainly.com/question/20693059

#SPJ2

Mike has a bank account whose balance is represented by A(t)=10,000*3.138^t. Where t is in years. Write the function so it reflects the monthly rate of interest . Around the nearest percent

Answers

9514 1404 393

Answer:

  A(m) = 10000×1.10^m; 10% monthly interest

Step-by-step explanation:

If t is the time in years and m is the corresponding time in months, then we have ...

  m = 12t

  t = m/12

So, the balance is ...

  A(t) = 10000×3.138^t

  A(m) = 10000×3.138^(m/12) = 10000×(3.138^(1/12))^m

  A(m) = 10000×1.10^m

The monthly interest rate is 10%.

_____

The monthly growth factor 1.10 is 1 more than the monthly growth rate.

  growth rate = growth factor -1 = 1.10 -1 = 0.10 = 10%.

Which inequality is represented by the graph below?

Answers

the answer to your question is 3

WILL GIVE U BRAINLIEST
True or False: All obtuse triangles are scalene?

Answers

Answer:

False

Step-by-step explanation:

an obtuse triangle maybe isosceles or scalene

A fruit salad recipe calls for 3/4 pound of apples and 2/5 pound of dates. What is the least common denominator of the fractions?
Group of answer choices

Answers

Answer:

20

Step-by-step explanation:

5 and 4 have no common factors until they are multiplied by each other. So if you were to convert your existing measurements, you would do the following.

(3/4) x (5/5)

(2/5) x (4/4)

Giving you 15/20 and 8/20

. The volume of a box is 405 cubic units. The length is x units, the width 4 units greater than the length, and the height is 9 units. Find the length and width of the box.

Answers

Answer:

length = 5

width = 9

Step-by-step explanation:

V = lwh

let 'x' = length

let '4+x' = width

9 = height

405 = 9x(4+x)

405 = 36x + 9x²

this is a quadratic equation:  9x² + 36x - 405 = 0

factor out a 9 to get:

9(x² + 4x - 45) = 0

9(x-5)(x+9) = 0

one root is 5 and the other is -9

since distance cannot be negative we use 5 as the length and 9 is the width

Harvey is often late for work. He leaves home late 60% of the time, but then drives very fast. This gives him a 50% chance of getting to work on time. When Harvey leaves home on time, he drives so slowly that he is late 70% of the time. What is the probability that Harvey left home on time if he gets to work on time

Answers

Answer:

40%

Step-by-step explanation:

Elena is conducting an experiment to determine if the high school students are more relaxed when the lights are off or when music is played during an exam. She selects 10 of her friends to take an exam with the lights off and another 10 of her friends to take an exam with music playing.

Required:
What is problematic about the way that Elena selected her groups?

Answers

Answer:

Problematic is that - only one factor should be analysed at a time. However she has considered both.

Step-by-step explanation:

Groups for any experimental study should be selected on the basis of one variable, other factor(s) remaining constant.

In this case, here are two variables - lights on or off, music playing or not playing - effecting relax level during exams.

She selects 10 students for exam with lights off , 10 for exam without music. This is problematic, as at once only lights or only music factor should be considered.

If one group is with light on , other should be with light off. If one group is with music, other should be without music. This mix up of one light off aspect & one music without music is inapt.

Similar Triangles

Write the ratio of corresponding sides for the similar triangles and reduce the ratio to lowest terms.

a. 14/27 = 21/28 = 14/27
b. 14/18 = 21/27 = 7/9
c. 14/21 = 18/27 = 2/3
d. 27/14 = 28/21 = 27/14

Please select the best answer from the choices provided

Answers

Answer:

B. 14/18 = 21/27 = 7/9

Step-by-step explanation:

I calculated it logically

The answer above me is correct

. In this exercise, you will conduct regression analysis with binary and categorical variables. (a) Use the command tabulate to show the categories of the variable occupation and their frequencies. What is the relative frequency of the category Sales

Answers

The answer is 85.q jjdhggehjejen

A rectangle measures 2
1
2
meters by 1
3
4
meters. What is its area?

Answers

Answer:

28408

Step-by-step explanation:

212x134=28408

u=(-4,10) and v=(5,3) what is 3v+u?

Answers

This is Right answer....

Help me PLEASEEEEEEEEEEEEE

Answers

Answer:

D. 44.55

Step-by-step explanation:

if you multiply 4.95x9 you get D

Answer:

the answer is D

Step-by-step explanation:

Since each is 4.95 multiply 4.95 x 9 = 44.55

hope this helps

enjoy

A skateboard ramp rises 2 feet for every 7 feet measured horizontally. What is the slope​?

Answers

Hopes this helps:

Answer: 2/7

A jar has 1 white marble and 2 red marbles in it. If Jerry picks out 2 marbles without looking inside, what is the probability that he will pick two of the same color?

A. 1/3
B. 1/2
C. 2/3
D. 3/2

Answers

Answer:

C) 2/3

Step-by-step explanation:

The 2 represents the two Jerry picked out and the 3 represents the total amount of marbles.

Hope this helped :)

Answer:

A.   1/3

Step-by-step explanation:

Chance of red on one marble

2/3

Chance of red on second marble

1/2

Chance both red

2/3 * 1/2 = 1/3

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