Confidence Intervals for Means
"Executives Whose Wives Stay at Home Earn More" was the headline for an article that appeared in the San Luis Obispo Telegram-Tribune (Oct. 14, 1994). To support this claim, the article presented data from a random sample of 231 married men who received MBA degrees in the late 1970s. The data are:
n Mean Salary Standard Deviation
Two-income family 140 $95,140 $15,000
Sole source of income 91 $124,510 $18,000
Construct a 95% confidence interval for the difference in these means.