Situation 1: Fred constructed a 95% confidence interval to estimate the average length (in minutes) of the movies he watches, with a random sample of 15 movies. He plans to continue collecting data until he has a random sample of 40 movies, and then find a new confidence interval.

Situation 2: Fred constructed a 95% confidence interval to estimate the average length (in minutes) of the movies he watches, with a random sample of 15 movies. He plans to continue collecting data until he has a random sample of 40 movies, and then find a new confidence interval. Which of these statements is most accurate?

Which of these statements is most accurate?

a

Both the standard error and the critical value will probably decrease for the larger sample.

b

Since 40 is a large sample, he will be able to use the Normal distribution.

c

The critical value will increase for the larger sample, but the standard error will probably decrease.

d

He should not perform inference at all, because he will probably continue watching movies for many years to come.

e

With this larger sample he can be more sure that his 95% confidence interval captures the true mean length of all movies he watches.