No, I have a less biased estimator for µ than were given in the problem (the two µ above) and the one I created which is µ=(X1+X2+X3)/3. Unbiased and less variance than the other two equations. I think my problem is that it confuses me that the equation is made up of a mean and a variance and not of variables, I don't know whether I should just treat those as variables or if there's some weird estimator thing that wasn't covered in my lecture/in the books.