Here is the Minitab output:

As the output mentions, recall that we were testing

H_{0}: μ_{1} - μ_{2} = 0

H_{a}: μ_{1} - μ_{2} > 0

and based on the small P-value, we rejected H_{0} 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 μ_{1} - μ_{2}. As we've seen in the previous tests, the confidence interval is provided only as part of the two-sided test.