Chapter 18, Problem 37E

Marriage In 1960, census results indicated that the age at which American men first married had a mean of 23.3 years. It is widely suspected that young people today are waiting longer to get married. We want to find out if the mean age of first marriage has increased since then.

1. a) Write appropriate hypotheses.
2. b) We plan to test our hypothesis by selecting a random sample of 40 men who married for the first time last year. Do you think the necessary assumptions for inference are satisfied? Explain.
3. c) Describe the approximate sampling distribution model for the mean age in such samples.
4. d) The men in our sample married at an average age of 24.2 years, with a standard deviation of 5.3 years. That results in a t-statistic of 1.074. What is the P-value for this?
5. e) Explain (in context) what this P-value means.
6. f) What’s your conclusion?