A researcher studying the sleep habits of teens will select a random sample of n n
teens from the population to survey. The researcher will construct a t
t
-interval to estimate the mean number of hours of sleep that teens in the population get each night. Which of the following is true about the t
t
-distribution as the value of n
n
decreases from 40 to 20 ?

The center decreases, and the area in the tails of the distribution increases.
The center decreases, and the area in the tails of the distribution increases.

The center increases, and the area in the tails of the distribution decreases.
The center increases, and the area in the tails of the distribution decreases.

The center remains constant, and the area in the tails of the distribution remains constant.
The center remains constant, and the area in the tails of the distribution remains constant.

The center remains constant, and the area in the tails of the distribution decreases.

In a recent telephone survey, 5,000 randomly selected teenagers were asked to cite their primary social network site. six of 10 teenagers said they use mybook as their primary social network site. a 95% confidence interval to estimate the true proportion of teenagers who use mybook as their primary social network site is found to be (0.2964, 0.9036). which of the following is a correct interpretation of the confidence level? ninety-five percent of all samples of this size would yield a confidence interval of (0.2964, 0.9036). there is a 95% chance that the true proportion of teenagers who use mybook as their primary social network site is in the interval (0.2964, 0.9036). ninety-five percent of the time, the procedure used to generate this interval will capture the true proportion of teenagers who use mybook as their primary social network site. ninety-five percent of all the samples of size 5,000 lie in the confidence interval (0.2964, 0.9036).