Section 9.2 Summary

1. The essential idea about hypothesis testing for the mean is as follows: When the observed value of is unusual or extreme in the sampling distribution of that assumes is true, we should reject . Otherwise, we should not reject .
2. The test statistic summarizes the information in the data set regarding the hypothesis test.
3. The critical region consists of the range of values of the test statistic for which we reject the null hypothesis. The value of that separates the critical region from the noncritical region is called the critical value .
4. In the critical-value method for the test for the mean, we compare with .