The distribution of grade point average for students at a large high school is skewed to the left with a mean of 3.53 and a standard deviation of 1.02.

a. Describe the shape of the sampling distribution of x¯ for SRSs of size n = 4 from the population of students at this high school. Justify your answer.

b. Describe the shape of the sampling distribution of x¯ for SRSs of size n = 50 from the Page Number: 480 population of students at this high school. Justify your answer.

Short Answer

Expert verified

a. The sample mean's sampling distribution is skewed to the left.

b. The sampling distribution of the sample mean is approximately normal.

Step by step solution

01

Part (a) : Step 1 : Given information 

Given :

Mean :3.53

Standard deviation :1.02.

Size n=4

02

Part (a) : Step 2 : Simplification 

The distribution of the population is skewed to the left.

n=4

Theorem of the center limit: The sampling distribution of the sample mean x is roughly normal if the sample size is 30or greater. The central limit theorem cannot be applied since the sample size of four is less than thirty. The sample mean's sampling distribution has the same shape as the population distribution in this example, hence the sample mean's sampling distribution is skewed to the left.

03

Part (b) : Step 1 : Given information 

Given :

Mean :3.53

Standard deviation : 1.02.

Sizen=50

04

Part (b) : Step 2 : Simplification 

The distribution of the population is skewed to the left.

n=50people

Theorem of the center limit: The sampling distribution of the sample mean is roughly normal if the sample size is 30or greater. Because the sample size of 50is greater than 30, the central limit theorem can be used, and the sampling distribution of the sample mean is approximately normal.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Which of the following statements about the sampling distribution of the sample mean is incorrect?

a. The standard deviation of the sampling distribution will decrease as the sample size increases.

b. The standard deviation of the sampling distribution measures how far the sample mean typically varies from the population mean.

c. The sample mean is an unbiased estimator of the population mean.

d. The sampling distribution shows how the sample mean is distributed around the population mean.

e. The sampling distribution shows how the sample is distributed around the sample mean.

A sample of teens A study of the health of teenagers plans to measure the blood cholesterol levels of an SRS of 13to 16year-olds. The researchers will report the mean xfrom their sample as an estimate of the mean cholesterol level μin this population. Explain to someone who knows little about statistics what it means to say that xis an unbiased estimator of μ.

Sample minimums List all 6possible SRSS of size n=2, calculate the minimum age for each sample, and display the sampling distribution of the sample minimum on a dotplot. Is the sample minimum an unbiased estimator of the population minimum? Explain your answer.

COLORAGE
RED1
WHITE5
SILVER8
RED20

What does the CLT say? Asked what the central limit theorem says, a student replies, "As you take larger and larger samples from a population, the variability of the sampling distribution of the sample mean decreases." Is the student right? Explain your answer.

Tall girls? To see if the claim made in Exercise 12is true at their high school, an Ap Statistics class chooses an SRS of twenty 16-year-old females at the school and measures their heights. In their sample, the mean height is 64.7inches. Does this provide convincing evidence that 16-year-old females at this school are taller than 64inches, on average?

a. What is the evidence that the average height of all 16-year-old females at this school is greater than 64inches, on average?

b. Provide two explanations for the evidence described in part (a).

We used technology to simulate choosing 250SRSs of size n=20from a population of three hundred 16-year-old females whose heights follow a Normal distribution with mean localid="1654113150676" μ=64inches and standard deviation μ=2.5inches. The dotplot shows x=the sample mean height for each of the 250simulated samples.

c. There is one dot on the graph at 62.5. Explain what this value represents.

d. Would it be surprising to get a sample mean of x=64.7or larger in an SRS of size 20when μ=64inches and σ=2.5inches? Justify your answer.

e. Based on your previous answers, is there convincing evidence that the average height of all 16-year-old females at this school is greater than 64inches? Explain your reasoning.

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free