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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.

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