A student went to the local county courthouse (in Cumberland County, Pennsylvania, in June and July of 1993) to gather data on ages of soon-to-be husbands and wives who had recently applied for marriage licenses. He gathered age data on a sample of 100 couples and calculated the difference in age (husband€“wife) for each couple. The results, which can be found in the file Marriage Ages on the textbook website, are displayed in the 3.CE.23 dotplot:
a. Write a paragraph describing the distribution of differences.
b. Do you consider it valid to use a theory-based confidence interval for a population mean, based on these sample data? Explain.
c. Determine a 99% confidence interval for the population mean.
d. Interpret the interval that you calculated in part (c).
e. Based on this confidence interval, do the sample data provide strong evidence for concluding that husbands tend to be older than their wives, on average? Explain how your answer follows from the confidence interval.
f. To what population of married couples do you feel comfortable generalizing the results of this study? Explain.

Transcribed Image Text:

12 16 -4 8 -8 Age difference (in years, husband – wife)