1.It is widely suspected that young people today are waiting longer to get married. We take a random sample of 50 men and find that their average age at first marriage is 28 years, with a standard deviation of 5.2 years. Then the 90% confidence interval is (26.765, 29.235). Which of the following gives a correct interpretation of this confidence interval?

Select one:

a.In 95% of samples, the average age of men at their first marriage is between 26.765 and 29.235 years.

b.Men marry for the first time when they are between 26.765 and 29.235 years old.

c.We are 90% confident that the average age of men at their first marriage is between 26.765 and 29.235 years.

d.None of these responses is correct.

2.An inventor has developed a new, energy-efficient lawn mower engine. From his stock of 2000 engines, the inventor selects a simple random sample of 76 engines for testing. The engines run for an average of 295 minutes, with a standard deviation of 20 minutes. The inventor finds that the 95% confidence interval is (290.43, 299.57) and says that he is 95% sure that the average run time for 76 engines is between 290.43 and 299.57 minutes. What is incorrect about his conclusion?

Select one:

a.None of these responses is correct.

b.The values of 290.43 and 299.57 are not correct.

c.The confidence interval is about the population mean (average run time of all his engines) not just the sample.

d.He should say he is confident not sure.

3.An inventor has developed a new, energy-efficient lawn mower engine. He claims that the engine will run continuously for 5 hours (300 minutes) on a single gallon of regular gasoline. We want to know if the average run time is different from 300 minutes. Which of the following gives a type II error?

Select one:

a.It is not possible to have a type II error.

b.We conclude that we don't have enough evidence to say that the lawn mowers have a run time different than 300 minutes and they actually have a run time of 300 minutes on a single gallon of regular gasoline.

c.We conclude that his lawn mowers have an average run time different from 300 minutes, when they actually do have a run time of 300 minutes on a single gallon of regular gasoline.

d.None of these responses is correct.

4.Do students who learned English as well as another language simultaneously score worse on the SAT Critical Reading exam than the general population of test takers? If we conclude that we do not have enough evidence to say the students who learned English and another language simultaneously score worse, when in reality they do score differently, what type of error did we make?

Select one:

a.Type I error

b.Type II error

c.This is not an error

d.Another type of error

5.We reduce the likelihood of a type II error, when we decrease the significance or?

level.

Select one:

True

False