I am learning on probabilities in populations and samples now but I'm stuck on this question.
Suppose we have a sample with n=35 of a population with a mean of 80 and standard deviation of 5.
What's the chance of the sample mean being between 79 and 82.
The only formula I got to solve this is this:
gekend means that it is known and
niet gekend unknown. So I suppose I should use the formula in the second row first column. Which I can't because I don't know S2.
I have searched everywhere but I can't figure it out maybe I am wording it wrong while searching for it.