Why is the chi-square distribution a good model for observed vs expected frequencies? I understand that the support of the chi-square $[0,\infty)$ coincides with the range of (expected - observed)^2, but what makes the chi-square the best model for this?

Hi, i am wondering how do you construct an univariate test when the null hypothesis is $1/n(\mu_1+\mu_2+\cdots+\mu_n)=k$ where k is a real number

@Simple Please ask that on the main site. There we have better facilities for asking & answering questions (e.g. formatting options will work) and the information will be available for people with the same question. That isn't a chat item.

oh, thank you.