A sociologist found that in a sample of 55 retired men, the average number of jobs they had during their lifetimes was 7.2. The population standard deviation is 2.4. Round intermediate and final answers to one decimal place. Part 1 The best point estimate of the mean is 7.2. Part 2 Find the 95% confidence interval of the mean number of jobs. 6.57 < ? < 7.83 Part 3 out of 4 Find the 99% confidence interval of the mean number of jobs. < ? <
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2 σ = 2.4 α/2 = 1.96 (from z-table for 95% confidence level) Calculate the margin of error: Margin of error = α/2 * σ / √n Margin of error = 1.96 * 2.4 / √55 Margin of error ≈ 0.6343 Calculate the confidence interval: Lower limit = x̄ - Margin of error Lower Show more…
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