Ans. When to use of
Z-test and T-test:-
Use of Z-test:-
- A z-test is a statistical test used to determine whether two
population means are different when the population variance
are known and the sample size is large
(n>30).
- In Z test, for Critical Z-vlaue we use Z table.
Use of t-test:-
- A t-test is a statistical
test used to determine whether two population means are different
when the population variances are
unknown and the sample size is small
(n<30).
- In t test, for Critical t-value we used t-table.
Note:- Both
methods assume a normal distribution of data.