1. Review for Exam III 2011, 11, 8

2. Today ’ s Topics How to decide which test to use? How to form hypotheses? Go over related-samples t-test slowly How to form research hypothesis and null hypothesis? How to compute std. err.?

3. One-Sample z-Test When the population mean (  ) and Std. Dev. (  ) are KNOWN, we use one-sample z-test to compare a single sample mean to the known population mean (  ). Key: Look for Population Std. Dev. (  )

4. One-Sample t-Test When the population Std. Dev. (  ) is UNKNOWN, we use one-sample t-test to compare a single sample mean to the known population mean (  ). We use the sample standard deviation (S) to estimate the Std. Err. Key: Look for Population Std. Dev. (  )

5. Related-Samples t-Test Situation 1: When we want to compare two samples that representing two populations (e.g., women vs. men), and the two samples are related, we use related-samples t-test to exam if one population mean is greater/less/equal to the other population mean. Situation 2: When we want to compare two set of scores collected from one sample, we use related- samples t-test to exam if posttest mean is greater/less/equal to pretest mean. Key terms: You must have two set of scores (two columns). The two set of scores must relate to each other.

6. Form a Research Hypothesis Tip: Start with the alternative hypothesis Key words for: < (  ): Decrease, less, below, worse, faster, etc. > (  ): Increase, greater, above, better, etc. Key words for  (=): Different, not equal, change, etc.

7. An Example of Related-Samples t-test

8. Recap Today ’ s Lecture How to decide which test to use? How to form hypotheses? Go over related-samples t-test slowly. Graph the distribution!!!