How are we to test a hypothesis of a sample Mean when the is unknown and the sample size is less than 30?
Enter the t-Distribution.
Properties of the t-Distribution
If a population is essentially normal, then the distribution is:
This is the equation for the Student t-Distribution, or simply t-Distribution, for all samples of size n less than 30.
To find the Rejection Region, we can use the t-Distribution Table. This table merely requires knowledge of the sample size, which allows us to calculate the Degrees of Freedom, and the Significance Level .
Degrees of Freedom = n - 1
Example: The Height of UCLA Basketball Players