You can find, in annexe, my point of view about the exercise.
I hope that it will help.
have been studying confidence intervals (CI) but I can't get this question.
A 95% CI for a mean mu is 85.3 +/- 2.35. Find the following CI for mu.
(a)90% (b) 99%
I guess that I'd express the 95% explicitly with every thing I know and then use simultaneous equ. maybe to find sigma and n.
If you could help me do one it would be much appreciated.