lets say i have 2 random variables X et Y. I also have N realizations drawns from both X and Y. For each collection of N samples, i compute the empirical mean of each, lets say x and y. What are some quantitative properties I can tell about the real mean of X and Y , from x and y? I have looked at tests of hypothesis. However it seems to me that the only possible tests will allow me to answer "is the mean of X above the mean of Y" or qualitative properties line this. Are there statistical tests that allow me to say "the mean of X is x with 99% confidence" or something like this? thanks!