Suppose that the sample proportion of students who did all their assigned homework last week is p^=57100=0.57. Would this sample proportion provide convincing evidence that less than 60%of all students at the school completed all their assigned homework last week? Explain your reasoning.

Short Answer

Expert verified

A sample proportion of p^0.57happened 78250=31.27%of the time, so it would not be surprising to get p^0.57. Since it is not surprising, it does not provide convincing evidence.

Step by step solution

01

Given information

We have been given that the sample proportion of students who did all their assigned homework last week is p^=57100=0.57

02

Explanation

The sample proportion (p^) refers to the percentage of people in a sample who have a particular attribute or trait. The sample proportion is the percentage of successful samples; to calculate it, divide the number of people (or objects) who have the desired feature by the total number of persons (or items) in the sample.

Because 78250=31.27%, of the values of p^in the simulation are less than or equal to 0.57, a sample fraction of p^=0.57or less in an SRS of size 100from a population with p =0.60 would not be surprising. A sample proportion of p^0.57does not provide convincing evidence that the population proportion of students who completed all of their assigned homework is less than p^=60%.

The disparity between the observed proportion (p^=0.57) and the proportion stated (p =0.60) could be explained by sampling variability.

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Most popular questions from this chapter

The Gallup Poll has decided to increase the size of its random sample of voters from about 1500 people to about 4000 people right before an election. The poll is designed to estimate the proportion of voters who favor a new law banning smoking in public buildings. The effect of this increase is to

a. reduce the bias of the estimate.

b. increase the bias of the estimate.

c. reduce the variability of the estimate.

d. increase the variability of the estimate.

e. reduce the bias and variability of the estimate.

You work for an advertising agency that is preparing a new television commercial to appeal to women. You have been asked to design an experiment to compare the effectiveness of three versions of the commercial. Each subject will be shown one of the three versions and then asked to reveal her attitude toward the product. You think there may be large differences in the responses of women who are employed and those who are not. Because of these differences, you should use

a. a block design, but not a matched pairs design.

b. a completely randomized design.

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d. a simple random sample.

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A 10-question multiple-choice exam offers 5 choices for each question. Jason just guesses the answers, so he has probability 15of getting any one answer correct. You want to perform a simulation to determine the number of correct answers that Jason gets. What would be a proper way to use a table of random digits to do this?

a. One digit from the random digit table simulates one answer, with 5 = correct and all other digits = incorrect. Ten digits from the table simulate 10 answers.

b. One digit from the random digit table simulates one answer, with 0 or 1 = correct and all other digits = incorrect. Ten digits from the table simulate 10 answers.

c. One digit from the random digit table simulates one answer, with odd = correct and even = incorrect. Ten digits from the table simulate 10 answers.

d. One digit from the random digit table simulates one answer, with 0 or 1 = correct and all other digits = incorrect, ignoring repeats. Ten digits from the table simulate 10 answers.

e. Two digits from the random digit table simulate one answer, with 00 to 20 = correct and 21 to 99 = incorrect. Ten pairs of digits from the table simulate 10 answers.

The central limit theorem is important in statistics because it allows us to use a Normal distribution to find probabilities involving the sample mean if the

a. sample size is reasonably large (for any population).

b. population is Normally distributed (for any sample size).

c. population is Normally distributed and the sample size is reasonably large.

d. population is Normally distributed and the population standard deviation is known (for any sample size).

e. population size is reasonably large (whether the population distribution is known or not).

According to the U.S. Census, the proportion of adults in a certain county who owned their own home was 0.71. An SRS of 100 adults in a certain section of the county found that 65 owned their home. Which one of the following represents the approximate probability of obtaining a sample of 100 adults in which 65 or fewer own their home, assuming that this section of the county has the same overall proportion of adults who own their home as does the entire county?

a. (10065)(0.71)65(0.29)3510065(0.71)65(0.29)35

b. (10065)(0.29)65(0.71)3510065(0.29)65(0.71)35

c.

P(z0.65-0.71(0.71)(0.29)100)Pz0.65-0.71(0.71)(0.29)100

d.P(z0.65-0.71(0.65)(0.35)100)Pz0.65-0.71(0.65)(0.35)100

e.P(z0.65-0.71(0.71)(0.29)100)Pz0.65-0.71(0.71)(0.29)100

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