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Z test for mean

10-29: According to the local union president, the mean gross income of plumbers in the Salt Lake City area follows the normal probability distribution with a mean $45,000 and a standard deviation of $3,000. A recent investigative reporter for KYAK TV found, for a sample of 120 plumbers, the mean gross income was $45,000. At the 0.10 significance level, is it reasonable to conclude that the mean income is not equal to $45,000? Determine the p-value.

10-57: The US President's call for designing and building a missile defense system that ignores restrictions of the Anti-Ballistic Missile Defense System treaty (ABM) is supported by 483 of the respondents in a nationwide poll of 1,002 adults. Is it reasonable to conclude that the nation is evenly divided on the issue? Use the .05 significance level.

Solution Summary

Step by step method for testing the hypothesis under 5 step approach is discussed here. Excel template for each problem is also included. This template can be used to obtain the answers of similar problems.