The article “Caffeine Knowledge, Attitudes, and Consumption in Adult Women” (J. of Nutrition Educ., 1992:

179–184) reports the following summary data on daily caffeine consumption for a sample of adult women:

, and

a. Does it appear plausible that the population distribution of daily caffeine consumption is normal? Is it necessary to assume a normal population distribution to test hypotheses about the value of the population mean consumption? Explain your reasoning.

b. Suppose it had previously been believed that mean consumption was at most 200 mg. Does the given data contradict this prior belief? Test the appropriate hypotheses at significance level .10 and include a P-value in your analysis.