1.Cheating:According to a report on academic cheating by ETS, the Educational Testing Service, college students majoring in Business and Engineering are more likely to cheat than students in other majors. For a statistics project, a community college student at Diablo Valley College (DVC) decides to investigate cheating in two popular majors at DVC: business and nursing. She convinces professors who teach business and nursing courses to distribute a short anonymous survey in their classes. The question about cheating is one of many other questions about college life.

From this data, the student plans to calculate a confidence interval for the difference in two population proportions. Which is the most reasonable description of the two populations for her conclusion?

2.Quit Smoking:The New England Journal of Medicine published the results of a double-blind, placebo-controlled experiment to study the effect of nicotine patches versus a placebo on quitting smoking.

With the data from the experiment we calculate the sample difference in the "quit smoking" rates for the nicotine treatment group and the placebo group ("treatment" minus "placebo"). We get 0.8%=0.008. The 99% confidence interval based on this sample difference is -0.1036 to 0.0882.

We also calculate a 90% confidence interval. How does the 90% confidence interval compare to the 99% confidence interval? For a 90% confidence interval, the margin of error (MOE) will:

3.In March 2015, the Public Policy Institute of California (PPIC) surveyed 7525 likely voters living in California. This is the 148th PPIC research poll, and is part of a survey series that started in 1998. PPIC researchers find that 3266 survey participants are registered Democrats and 2137 survey participants are registered Republicans. PPIC is interested in the difference in approval rate for the governor between registered Democrats and registered Republicans in California.

Participants were asked: "Overall, do you approve or disapprove of the way the governor of California is handling his job?" 2450 of the registered Democrats answered "Yes" and 684 of the registered Republicans answered "Yes."

True or false? A normal model is an appropriate fit for the sampling distribution of sample differences.

4.In March 2015, the Public Policy Institute of California (PPIC) surveyed 7,525 likely voters living in California. In the survey, respondents were asked about global warming. PPIC researchers are interested in the difference in viewpoints across racial/ethnic groups. PPIC results show that 75% of Latinos view global warming as a serious problem, and 46% of whites view global warming as a serious problem.

Using the data from the survey, we calculate the sample difference in global warming viewpoints for Latino respondents and white respondents to be 29% = 0.29.

Researchers can use the 29% sample difference to draw a conclusion about which populations?

1. Latinos and whites living in the United States who are likely voters
2. Latinos and whites who live in California
3. Latinos and whites living in California who are likely to vote
4. Latinos and whites who live in California and are concerned about global warming

5.In March 2015, the Public Policy Institute of California (PPIC) surveyed 7525 likely voters living in California. In the survey, respondents were asked about global warming. PPIC researchers are interested in the difference in viewpoints across racial/ethnic groups. PPIC results show that 75% of Latinos view global warming as a serious problem, and 46% of whites view global warming as a serious problem.

Using the data from the survey, we calculate the sample difference in global warming viewpoints for Latino respondents and white respondents to be 29% = 0.29. The 95% confidence interval based on this sample difference is (0.275, 0.305).

Which of the following is avalidconclusion? Check all that apply.

1. We are 95% confident that the proportion of Latinos who view global warming as a serious problem is about 27.5% to 30.5% lower than the proportion of whites who view global warming as a serious problem.
2. We are 95% confident that the true difference in proportion of Latinos who view global warming as a serious problem and whites who view global warming as a serious problem is 27.5% to 30.5%.
3. We are 95% confident that the difference between Latino and white opinions about the severity of global warming is 29% with a margin of error of 1.5%.

6.TheNew England Journal of Medicinepublished the results of a double-blind, placebo-controlled experiment to study the effect of nicotine patches and the antidepressant bupropion on quitting smoking.

With the data from the experiment we calculate the sample difference in the "quit smoking" rates for the nicotine treatment group and the placebo group ("treatment" minus "placebo"). We get 0.8% = 0.008. Which of the following is an appropriate conclusion based on this finding?

1. In this experiment the nicotine treatment had a higher success rate than the placebo group, but the improvement was less than 1%.
2. In this experiment, the placebo group had a higher success rate than the nicotine group by 0.8%.
3. Nicotine patches will produce a slightly higher success rate when compared to a placebo, but the difference is not statistically significant.
4. Nicotine patches and the antidepressant bupropion work equally well on "quit smoking" rates.

7.The difference between teenage female and male depression rates estimated from two samples is 0.08. The estimated standard error of the sampling distribution is 0.04. What is the 95% confidence interval? Use the critical value z = 1.96.

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Round all calculations to two decimal places. Put lower bound in the first box and upper bound in the second box.

8.Quit Smoking:Previous studies suggest that use of nicotine-replacement therapies and antidepressants can help people stop smoking. The New England Journal of Medicine published the results of a double-blind, placebo-controlled experiment to study the effect of nicotine patches and the antidepressant bupropion on quitting smoking. The target for quitting smoking was the 8th day of the experiment.

In this experiment researchers randomly assigned smokers to treatments. Of the 158 smokers taking a placebo, 27 stopped smoking by the 8th day. Of the 253 smokers taking only the antidepressant buproprion, 76 stopped smoking by the 8th day. Calculate the estimated standard error for the sampling distribution of differences in sample proportions.

The estimated standard error =

Round your answer to three decimal places.

9.Quit Smoking:Previous studies suggest that use of nicotine-replacement therapies and antidepressants can help people stop smoking. The New England Journal of Medicine published the results of a double-blind, placebo-controlled experiment to study the effect of nicotine patches and the antidepressant bupropion on quitting smoking. The target for quitting smoking was the 8th day of the experiment.

In this experiment researchers randomly assigned smokers to treatments. Of the 162 smokers taking a placebo, 28 stopped smoking by the 8th day. Of the 272 smokers taking only the antidepressant buproprion, 82 stopped smoking by the 8th day.

Calculate the 99% confidence interval to estimate the treatment effect of buproprion (placebo-treatment). (The standard error is about 0.0407. Use critical value z = 2.576.)

(,)

Round your answer to three decimal places. Put lower bound in the first box and upper bound in the second box.

10.Gardeners on the west coast of the United States are investigating the difference in survival rates of two flowering plants in drought climates. Plant A has a survival rate of 0.68 and plant B has a survival rate of 0.44. The standard error of the difference in proportions is 0.081. What is the margin of error for a 99% confidence interval? Use critical value z = 2.576.

MOE =

Round all calculations to three decimal places.

11.The 99% confidence interval for the difference in proportions of women and men who support stricter gun control is (0.02, 0.08). (Difference here is "women" minus "men.") Which of the following conclusions about the confidence interval is most appropriate?

1. 99% of the time the gender difference seen in a poll on this issue is between 0.02 and 0.08.
2. We are 99% confident that the difference between the proportions of women and men who support stricter gun control is between 0.02 and 0.08.
3. There is a 99% chance that the difference between the proportions of women and men who support stricter gun control is between 0.02 and 0.08.