The following MINITAB output presents the results of a power calculation for a test concerning a population mean μ.

a. Is the power calculated for a one-tailed or two-tailed test?

b. Assume that the value of μ used for the null hypothesis is μ = 3. For what alternate value of μ is the power calculated?

c. If the sample size were 25, would the power be less than 0.85, greater than 0.85, or is it impossible to tell from the output? Explain.

d. If the difference were 0.5, would the power be less than 0.90, greater than 0.90, or is it impossible to tell from the output? Explain.

e. If the sample size were 17, would the power be less than 0.85, greater than 0.85, or is it impossible to tell from the output? Explain.

Transcribed Image Text:

Power and Sample Size 1-Sample t Test Testing mean = null (versus > null) Calculating power for mean = null + difference Alpha = 0.05 Assumed standard deviation = 1.5 Sample Size Target Power Difference Actual Power 1 18 0.85 0.857299