1. 7.3 Hypothesis Testing for the Mean ( unknown)
Key Concepts:
Student’s t-distribution
Critical Values and Rejection Regions
The t-test for a Population Mean

2. 7.3 Hypothesis Testing for the Mean ( unknown)
Why do we need another test for µ?
If we do not know σ, then we cannot use the z-test from the last section.
Instead we use the ‘studentized’ version of the sample mean as our test statistic and the t-distribution to find our critical values.
Note: we use n-1 degrees of freedom when we look for our critical values
Practice finding critical values:
#6 p (right-tailed test)
#8 (two-tailed test)

3. 7.3 Hypothesis Testing for the Mean ( unknown)
Things to know about the t-test for µ:
Assumes σ is unknown and either the population is normally distributed or n  30.
The test statistic is the studentized version of the sample mean:
Always use the t-curve with n-1 degrees of freedom.

4. 7.3 Hypothesis Testing for the Mean ( unknown)
Guidelines for using the t-Test for µ are given on page 379.
#16 p (IRS Wait Times)
#22 p (Annual Pay)