1. Average years of education are reported by social class based on data from the GSS 2018.

	Mean	Standard Deviation	N
Lower class	12.19	3.08	102
Working class	13.16	2.93	523
Middle class	14.60	2.88	498
Upper class	15.21	3.01	34

a. Construct the 95% confidence interval for the mean number of years of education for lower- and working-class respondents.

b. Construct the 99% confidence interval for the mean number of years of education for lower-class and middle-class respondents.

c. As our confidence in the result increases, how does the size of the confidence interval Change? Explain why this is so.

2. In 2016, the Pew Research Center conducted a survey of 1,004 Canadians and 1,003 Americans to assess their opinion of climate change. The data show that 51% of Canadians and 45% of Americans believe climate change is a very serious problem.⁷

a. Estimate the proportion of all Canadians who believe climate change is a very serious problem at the 95% confidence interval.

b. Estimate the proportion of all Americans who believe climate change is a very serious problem at the 95% confidence interval.

c. Would you be confident in reporting that the majority (51% or higher) of Canadians and Americans believe climate change is a very serious problem? Explain.

3. Though 70% of women with children younger than 18 years participate in the labor force,⁸society still upholds the stay-at-home mother as the traditional model. Some believe that employment distracts mothers from their parenting role, affecting the well-being of children.

a. In the GSS 2014, respondents were asked to indicate their level of agreement to the statement, "A working mother hurts children." Of the 435 male respondents who answered the question, 18% strongly agreed that a working mother does not hurt children. Construct a 90% confidence interval for this statistic.

b. Of the 566 female respondents who answered the question, 40% strongly agreed that a working mother does not hurt children. Construct a 90% confidence interval for this statistic.

c. Why do you think there is a difference between men and women on this issue?

4. You have been doing research for your statistics class on the prevalence of binge drinking among teens.

a. According to 2011 Monitoring the Future data, the average binge drinking score, for this sample of 914 teens, is 1.27, with a standard deviation of 0.80. Binge drinking is defined as the number of times the teen drank five or more alcoholic drinks during the past week. Construct the 95% confidence interval for the true average severe binge drinking score.

b. Your roommate is concerned about your confidence interval calculation, arguing that severe binge drinking scores are not normally distributed, which in turn makes the confidence interval calculation meaningless. Assume your roommate is correct about the distribution of severe binge drinking scores. Does that imply that the calculation of a confidence interval is not appropriate? Why or why not?