In Example 11.12 (p. 428), we learned about a study of hangover symptoms in college students (Slutske et al., 2003, on the website for this book). The students answered questions about alcohol use and hangovers, including a count of how many out of a list of 13 possible hangover symptoms that they had experienced in the past year. For the 470 men, the mean number of symptoms was 5.3; for the 755 women, it was 5.1.

The standard deviation was 3.4 for each of the two samples.

a. Define the parameter of interest for comparing men and women using appropriate notation.

b. Find the standard error of the difference in means.

c. Find an approximate 95% confidence interval for the difference in population means.

d. On the basis of your interval in part (c), do you think that there is a difference in the population mean number of hangover symptoms experienced by college men and women? Explain.