Repeat Exercises 10.4 through 10.6 using the unequal variances procedure. Compare your results to those obtained using the equal variances procedure.
In Exercises 10.4 Calculate a 95 percent confidence interval for μ1 – μ2. Can we be 95 percent confident that μ1 – μ2 is greater than 20? Explain why we can use the equal variances procedure here.
In Exercises 10.5 Use critical values to test the null hypothesis H0: μ1 – μ2 ≤ 20 versus the alternative hypothesis H0: μ1 – μ2 > 20 by setting α equal to .10, .05, .01, and .001. How much evidence is there that the difference between μ1 and μ2 exceeds 20?
In Exercises 10.6 Use critical values to test the null hypothesis H0: μ1 – μ2 = 20 versus the alternative hypothesis H0: μ1 – μ2 ≠ 20 by setting a equal to .10, .05, .01, and .001. How much evidence is there that the difference between μ1 and μ2 is not equal to 20?