Final Test Information

1. Final Test Information • The final test is Monday, April 13 at 8:30 am • GRH102: Last name begins with A - I • GRH106: Last name begins with K - Z • The exam is out of 40: 15 multiple choice (worth 15); 5 short answer (worth 25) • It will cover material from the entire course, but the focus will be on ANOVA and correlation • You will need to be able to identify when to do a z-test, t-test, ANOVA, and correlation • Not all of the short-answer questions require calculations

2. Statz Rappers

3. The Basics of Hypothesis Testing • State the null and research hypotheses in words and symbols • Determine the level of significance • Identify the critical value • Calculate the test statistic • Evaluate the test statistic in light of the critical value • Make a decision about the null hypothesis • State your conclusions in plain language

4. Statistical Tests: Single sample mean • Used to compare a single sample to a population • Is the sample significantly different from the population? H0: µ = X H1: µ ≠ X • If you know the population standard deviation, then use a z-test • If you do not know the population standard deviation, then use a t-test

5. Statistical Tests: T-test for two related samples • Used to compare two groups that are related in some way • Are the two groups significantly different from each other? H0: µD = 0 H1: µD ≠ 0 • Could be a pre/post (i.e., before/after) design • Could be two groups whose participants are related in some way (couples, twins, siblings etc).

6. Statistical Tests: T-test for two independent samples • Used to compare two groups that are independent of each other • Are the two groups significantly different from each other? Ho: µ1 = µ2 H1: µ1 ≠ µ2

7. Statistical Tests: Analysis of variance • Used to compare three or more groups • Are the groups significantly different from each other? Ho: µ1 = µ2 = µ3 H1: µ1 ≠ µ2≠ µ3 • If you reject your null hypothesis and conclude that there is a difference between the groups, you need to conduct post hoc (Tukey HSD) tests to determine which groups are different

8. ANOVA Summary Table Source df SS MS F Between K-1 MSB*dfB SSB/dfB MSB/MSW Within N-K MSW*dfW SSW/dfW Total N-1 SSB + SSW

9. Statistical Tests: Correlation • Used to determine if there is a relationships between two variables • Are the variables significantly correlated with each other? H0: r = 0 H0: r ≠ 0 • There are three ways to describe the relationship between the variables: • The direction and strength of the relationship (i.e., is r positive or negative, and how close is it to 1.0?) • Is r significant (compare obtained value of r to critical value)? • The amount of variance in one variable explained by the other (i.e., r2, the coefficient of determination)

10. Experimental Looks for differences between groups of scores Uses terms like “effect”, “difference”, “cause” Use z-test, t-test or ANOVA to analyze data Correlational Looks for relationships between groups of scores Uses terms like “relationship”, “correlation” Use correlation to analyze data Study Designs

11. Data Analysis Decision Tree for Experimental Designs How many groups? 1 group (comparesample to population) 2 groups Do a t-test 3 or moregroups Do an ANOVA Do you know the populationstandard deviation? Are the scores related? Is Fobt ≥ Fcrit? No Do not reject H0 No T-test for single samples Yes Z-test forsinglesamples No T-test for independent samples Yes T-test for relatedsamples Yes Reject H0 Conduct HSD post hoc test