The rejection region for a hypothesis test is also called the critical region.

In a two-tailed test, the null hypothesis should not be rejected when the test value is on either of the two critical regions.

Hypothesis testing is basically testing an assumption that we make about the population parameter.

In the given, Null hypothesis: mu = 21.5 and altenatvie hypothesis: mu > 21.5 show a one-tailed test since it shows direction of the distribution.

A two-tailed test shows that the null hypothesis may be rejected when the test value is on the critical region on either side of the distribution.

We don’t need to set the level of the significance because we can get 100% accuracy level in testing hypothesis.

The alternative hypothesis is a statement that there is no significance difference between the two given properties.

The two types of significance test are one-tailed and twotailed test

The level of significance refers to the degree of significance in which we reject or fail to reject the null hypothesis.

The notation mu and zigma are sample values.