It is actually the Simple Linear Regression Analysis Question
For diabetics with an initial weight the same as yours, calculate the 95% confidence interval on their predicted mean weight loss at one year after DBI therapy.
For an individual diabetic with an initial weight the same as yours, calculate the 95% confidence interval on his predicted weight loss at one year after DBI therapy
1. Confidence interval for the mean response (E(Y)) at a fixed level of the regressor variable (X).
2. Prediction interval of one individual future point Y at a fixed level of the regressor variable (X).
Any standard regression text has examples for these two cases in the chapter on simple linear regression. If these questions are from an ongoing test, then it is inappropriate to seek answers here.