# 9: Introduction to t-tests

- Page ID
- 14502

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- 9.1: The t-statistic
- The z-statistic was a useful way to link the material and ease us into the new way to looking at data, but it isn’t a very common test because it relies on knowing the populations standard deviation, σ, which is rarely going to be the case. Instead, we will estimate that parameter σ using the sample statistic s in the same way that we estimate μ using X. Our new statistic is called t, and for testing one population mean using a single sample (called a 1-sample t -test)

- 9.2: Hypothesis Testing with t
- Hypothesis testing with the t-statistic works exactly the same way as z-tests did, following the four-step process of (1) Stating the Hypothesis, (2) Finding the Critical Values, (3) Computing the Test Statistic, and (4) Making the Decision.