METHODS AND APPLICATIONS
9.51 Suppose that a random sample of 16 measurements from a normally distributed population gives a sample mean of and a sample standard deviation of s = 6. Use critical values to test H0: μ ≤ 10 versus Ha: μ > 10 using levels of significance α = .10, α = .05, α = .01, and α = .001. What do you conclude at each value of α?
9.52 Suppose that a random sample of nine measurements from a normally distributed population gives a sample mean of and a sample standard deviation of s = .3. Use critical values to test H0: μ = 3 versus Ha: μ ≠ 3 using levels of significance α = .10, α = .05, α = .01, and α = .001. What do you conclude at each value of α?
9.53 THE AIR TRAFFIC CONTROL CASE AlertTime
Recall that it is hoped that the mean alert time, μ, using the new display panel is less than eight seconds. Formulate the null hypothesis H0 and the alternative hypothesis Ha that would be used to attempt to provide evidence that μ is less than eight seconds. The mean and the standard deviation of the sample of n = 15 alert times are and s = 1.0261. Perform a t test of H0 versus Ha by setting α equal to .05 and using a critical value. Interpret the results of the test.