1. The data in file XR11100 are the weights (in grams) for random samples of grain packages filled by two different filling machines. The machines have a fine adjustment for the mean amount of fill, but the standard deviations are inherent in the design of the grain deliv- ery mechanism. Based on these data, and using the 0.01 level of significance, is there reason to conclude that the population standard deviations might not be equal for the quantities being delivered from the two machines? Identify and interpret the p-value for the test.
2. An anthropologist studying personal advertise- ments in a Utica, New York, newspaper has observed whether the advertiser included a mention of an inter- est in the outdoors in his or her ads. According to the anthropologist, citing the outdoors "may be taken to imply not only good life habits, but also sound char- acter." Overall, 58% of men and 62% of women men- tioned the outdoors in their ad. Assuming that the data are in file XR11101, coded as 1 5 did not mention the outdoors and 2 5 mentioned the outdoors, use the 0.10 level of significance in examining whether the population percentages for men and women who mention the out- doors might be the same. Identify and interpret the p-value for the test, then construct and interpret the 90% confidence interval for the difference between the population proportions.
Source: Karen S. Peterson, "Personal Ads Get Back To Nature," USA Today, November 23, 1999, p. 1D.