A recent rash of retirements from the U.S. Senate

@ SOLWASTE.DAT prompted Middlebury College researchers J. E.Trickett and P. M. Sommers to study the ages and lengths of service of members of Congress (Chance, Spring 1996)

One question of interest to the researchers is: "Did the 13 senators who decided to retire in 1995-1996 begm their careers at a younger average age than did the rest of their colleagues in the Senate?"

a. The average age at which the 13 retiring senators began their service is 45.783 years; the correspondins average for all other senators is 47.201 years. Is this sufficient information to answer the researchers'

question? Explain.

b. The researchers conducted a two-sample t-test on the difference between the two means. Specify the null and alternative hypotheses for this tcst. Clearly define the parameter of interest.

c. The observed significance level for the test, part b, was reported as p = .55. Interpret this result.