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Statistics: Hypothesis Test, Confidence Interval Approach

1. In 2001, the US Department of Labor reported the average hourly earnings for US production workers to be $14.32 per hour. A sample of 75 production workers during 2003 showed a sample mean of $14.68 per hour. Assuming the population standard deviation is $1.45, can we conclude that an increase occurred in mean hourly earnings since 2001? Perform a hypothesis test. Use alpha=0.05 .

2. Assume that the average number of hours of watching TV for a week for grade 12 students in a province is 15 hours. A sample of 50 students from ABC High School provided a sample mean of 14.15 hours. The population standard deviation is 3 hours.
(a) Test if the average number of hours spent in watching TV for this high school is different from the provincial average at 0.02 significance level.
(b) Use the confidence interval approach to test the hypothesis in (a).

Solution Summary

This solution is comprised of detailed step-by-step calculations and analysis of the given problems and provides students with a clear perspective of the underlying concepts. The calculations have been shown in Interactive EXCEL sheets for better understanding.