Question

小吉

想請問這題怎麼解

For the following cases, identify which distribution, z or t, should be used in calculating the statistical intervals of population mean (u).
If the confidence interval could not be estimated under the given conditions, just put an "X".
(a). (3%) Population is not normally distributed and its variance
is given, sample size n = 22. Ans:( )
(c). (3%) Population is normally distributed and its variance is
given, sample size n = 11. Ans:( )
(b). (3%) Population is a uniform distribution and its variance is (d). (3%) Population is normally distributed and its variance is
unknown, sample size n = 13. Ans:( )
unkown, sample size n = 18. Ans:( )