Chapter 8.2, Problem 44E

a)

To determine

To explain why do not have enough information to give confidence intervals for millennials and baby boomers separately.

Explanation of Solution

Given:

The study reported that 85% of millennials included 9/11 in their top-10 and 70% of baby boomers included 9/11.

For every confidence interval to be find, we need sample size, sample proportion and confidence level. As sample size not given so it is not possible to construct confidence interval.

b)

To determine

To explain whether 95% confidence interval for baby boomers would have a larger or smaller margin of error than the estimate from exercise 42.

Explanation of Solution

Given:

The study reported that 85% of millennials included 9/11 in their top-10 and 70% of baby boomers included 9/11.

When decreasing the sample size then the baby boomers in the sample will be less than all individuals in the sample. Therefore, if the sample size decrease, then we will get less information about the population. So, our estimates will be less accurate. Less accurate estimate means there are less chances that true population proportion contains in the confidence interval. Therefore, the confidence interval needs to be wider. Since the margin of error is half the width of the confidence interval, the margin of error is larger.