The human resources department of a consulting firm gives a standard creativity test to a randomly selected group of new hires every year. This year, 50 new hires took the test and scored a mean of 111.6 points with a standard deviation of 14.3. Last year, 55 new hires took the test and scored a mean of 118.4 points with a standard deviation of 15.6 . Assume that the population standard deviations of the test scores of all new hires in the current year and the test scores of all new hires last year can be estimated by the sample standard deviations, as the samples used were quite large. Construct a 99% confidence interval for u1-u2 , the difference between the mean test score u1 of new hires from the current year and the mean test score of u2 new hires from last year.
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