For a new study conducted by a fitness magazine, 240 females were randomly selected. For each, the mean daily calorie consumption was calculated for a September-February period. A second sample of 245 females was chosen independently of the first. For each of them, the mean daily calorie consumption was calculated for a March-August period. During the September-February period, participants consumed a mean of 2375 calories daily with a standard deviation of 202. During the March-August period, participants consumed a mean of 2425 calories daily with a standard deviation of 267.5. The population standard deviations of daily calories consumed for females in the two periods can be estimated using the sample standard deviations, as the samples that were used to compute them were quite large. Construct a 99% confidence interval for -μ1μ2, the difference between the mean daily calorie consumption μ1 of females in September-February and the mean daily calorie consumption μ2 of females in March-August. Then complete the table below.

I don't even know where to start with this problem.

So far I have

Trial 1: Trial 2:

240 selected 245 selected

Mean: 2,375 cal Mean: 2,425

SD= 202 SD= 267.5