A simple random sample of 60 items resulted in a sample mean of 80. The population standard deviation is σ = 15. Compute the 95% confidence interval for the population mean. Round your answers to one decimal place. Assume that the same sample mean was obtained from a sample of 120 items. Provide a 95% confidence interval for the population mean. Round your answers to two decimal places. What is the effect of a larger sample size on the interval estimate? Larger sample provides a _____ margin of error.
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Given: Sample mean (x̄) = 80 Population standard deviation (σ) = 15 Sample size (n) = 60 Confidence level = 95% Z-score for 95% confidence level = 1.96 Margin of error (E) = Z * (σ / √n) E = 1.96 * (15 / √60) E = 1.96 * (15 / 7.746) E = 1.96 * 1.937 E = 3.7955 Show more…
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