# Z-Estimate

In an attempt to reduce the number of person-hours lost as a result of industrial accidents, a large production plant installed new safety equipment. In a test of the effectiveness of the equipment, a random sample of 50 departments was chosen. The number of person-hours lost in the month prior to and the month after the installation of the safety equipment was recorded. The percentage change was calculated, and the data stored in excel file . Assume that the population standard deviation is 5 . Can we infer at the 10% significance level that the new safety equipment is effective?

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#### Solution Summary

In an attempt to reduce the number of person-hours lost as a result of industrial accidents, a large production plant installed new safety equipment. In a test of the effectiveness of the equipment, a random sample of 50 departments was chosen. The number of person-hours lost in the month prior to and the month after the installation of the safety equipment was recorded. The percentage change was calculated, and the data stored in excel file . Assume that the population standard deviation is 5 . Can we infer at the 10% significance level that the new safety equipment is effective?