PSY 418 – Burnham Spring, 2004

Exam III Information

Material

Text: Chapters, 9, 10, 11, 12, Epilogue, and Appendix B

Handouts; “Correlation”, “Chi-Square (c²) Tests”, “Chi-Square – Some Sample Problems” “Chi-Square—Some Answers”

Some Information to Know and Exercises to Review

Statistics

Thoroughly understand the material in the handout titled “Correlation”: Know the z-score formula for r, be able to estimate r from scatterplots , understand and be able to apply the factors that do and do not affect the magnitude of r and understand the issues having to do with correlation and causality and approaches to overcoming those problems. Know how to use the table of critical values of r to determine whether an r is statistically significant. Understand the difference between statistically significant values of r and meaningful values of r. (An r must be statistically significant for it to be meaningful, but just because it is statistically significant it is not necessarily meaningful.)

You should know how to use the z-score prediction equation to do the sort of problems given in that handout. Thus you will also have to know how to convert a score to a z-score and how to convert a z-score to a score. You should also know how to apply the raw score prediction formula. (If regression problems are on the exam, you will be given the formulas, but you need to know how to apply them.)

You should know how to apply the formula for the computation of chi-square. (You will be given the formula, but you will need to know how to compute the observed frequencies) Know how to do the sample problems and use the table of critical values of chi-square to determine whether an obtained chi-square is statistically significant.

You should also know how to report the results of correlational and chi-square analyses.

Glossary

There will be glossary questions in which you will be asked to label definitions or examples of the glossary terms with the appropriate term. All of the glossary terms tested from Chapters 10, 11, and 12 are will either be in the lecture notes (on the home page) and/or part of the recommended text exercises and questions (see over) for these chapters.

over

Text Exercises and Questions

Chapter 9 ‘Short Essay’, esp. 2, 3, 4, 5, 7, 11, and 12,

Exercise 9.1.: Think about directionality and third-variable problems that may underlie these correlations. If there are third-variable problems, what could you do to determine whether a particular third variable was a relevant third variable, and what pattern of correlations and what results would indicate that it was or was not a relevant third variable? (You should know what a partial correlation coefficient does.) If there are directionality problems, what might you be able to do to correctly infer the direction of the association? (You should know about cross-lagged panel studies.)

Exercise 9.3: You should be able to come up with a rough estimate of r from scatterplots and draw a scatterplot that approximately illustrates an r.

Exercise 10.1.: Identify which threat or threats are most likely and specify why.

Exercise 10.3.: You know that the incidence was high the year before the law and low the year after it was imposed. The question is: What data points for other years before the introduction of the law and what data points for additional years after the introduction of the law would lead you to make each of the four conclusions? Draw four (not three) such time series graphs, one for each pattern of results.

Chapter 11 ‘Short Essay’, especially 3. Also think about the conditions under which modern psychologists seem willing to accept the results of small-N research and the reasons why they are willing to do so.

Exercise 11.2. This exercise should help you to learn the language of applied behavior analysis and the patterns of results that can lead to a conclusion that the intervention is effective. You should know the names and characteristics of these designs.

Exercise 12.1.: Also see Appendix B.

Exercise 12.2.: I like the focus on contexts (where one would conduct the observations and whether one would create some structure for the observations) and operational definitions.

Exercise 12.3.: This exercise should help you learn the relevant terms.