Question

In a two-tail test for the population mean, if we decided in favor of the alternative hypothesis when the null hypothesis is false,
A. a Type II error is made
B. a one-tail test should be used instead of a two-tail test
C. a correct decision is made
D. a Type I error is made

In a one-tail test for the population mean, if we decide in favor of the null hypothesis when the alternative hypothesis is true,
A. a two-tail test should be used instead of a one-tail test
B. a Type II error is committed
C. no error has been made
D. a Type I error is committed

Answer 1

Solution:

In a two-tail test for the population mean, if we decided in favor of the alternative hypothesis when the null hypothesis is false,
C. a correct decision is made

In a one-tail test for the population mean, if we decide in favor of the null hypothesis when the alternative hypothesis is true,
B. a Type II error is committed

Explnation:

Type I error : Reject the null hypothesis when the null hypothesis is true,

Type II error : Fail to reject the null hypothesis , when the null hypothesis is not true.