Minitab Instructions: Two Independent Samples

Here is the Minitab output:


As the output mentions, recall that we were testing

H0: μ1 - μ2 = 0

Ha: μ1 - μ2 > 0

and based on the small P-value, we rejected H0 and concluded that males 20-29 years old weigh more, on average, than males 75+ years old. It would be interesting to follow up this conclusion and estimate how much more males 20-29 years old weigh, on average. The 95% confidence interval does exactly that. Note, however, that the output does not contain the 95% confidence interval for μ1 - μ2. As we've seen in the previous tests, the confidence interval is provided only as part of the two-sided test.