Research Methods and Statistics

Janie Wilson received her PhD in Experimental Psychology from the University of South Carolina in 1994. Since that time, she has been teaching and conducting research at Georgia Southern University. In the classroom, Dr. Wilson specializes in teaching and learning in statistics and research methods. Research interests include rapport in teaching based on empirical data on the first day of class, electronic communications, interactions with students in a traditional classroom, syllabus design, and the development and validation of the Professor-Student Rapport Scale. Recent publications include two brief texts with SAGE: An EasyGuide to Research Presentations and An EasyGuide to Research Design and SPSS. Along with her colleague, Shauna Joye, she recently published Research Methods and Statistics: An Integrated Approach with SAGE. Dr. Wilson has contributed numerous chapters to edited books and has co-edited several books related to teaching and learning. She has published extensively on the scholarship of teaching and learning and has offered over 60 conference presentations, including several invited keynote addresses. Dr. Wilson is the Past President of the Society for the Teaching of Psychology (STP), Division Two of APA. Dr. Shauna Joye I earned a B.S. in Biology from Georgia Southern University and a Ph.D. in Psychology from Florida State University. During graduate and post-doctoral training, my research and clinical work focused on early childhood learning, attention disorders, temperament, and autism spectrum disorder, with an emphasis on measurement of these constructs. Currently, I am a faculty member at Georgia Southern University, and I examine clinical interventions to enhance self-control, including empirical research in mindfulness. I also work with combat veterans to determine the impact of therapeutic wilderness experiences on wellness. Finally, I continue to pursue a long-standing commitment to teaching and learning through scholarship in that area. I enjoy working with undergraduate and graduate students who are interested in learning more about the process of research, from study design and analysis to APA-style writing. Outside of teaching at Georgia Southern University, I maintain a private practice where I work as a child and adolescent therapist. My association memberships include the American Psychological Association, Society for Teaching of Psychology, Wilderness Medical Society, and Association for Psychological Science.

Preface Acknowledgments About the Authors Section I- Foundations of Design and Analysis Chapter 1- The Scientific Method Empirical Data Step 1: Ask a Question Choose a Topic Ask a Simple Question Step 2: Read the Published Literature Locate Research Choose a Specific Question Step 3: Create a Method Step 4: Collect and Analyze Data Step 5: Answer the Research Question Step 6: Share Your Results Research in Psychology: APA Style Summary Review of Terms Practice Items References Chapter 2- Ethical Research Ethical Treatment of Participants Assessing Risk to Participants Literature Review Hypothesis The Sample Method Statistics and the Data Benefits Risk Appendices Personnel Certification of Ethics Training Deception Testing of Special Populations Medical Procedures Animal Research Informed Consent Treating Participants Ethically Ethics After Testing Participants Data Entry Data Analysis Writing a Presentation or Manuscript Authorship Issues Presenting and Publishing Research Who Is Harmed by Unethical Behavior? Ethical Data-Collection Methods Summary Review of Terms Practice Items References Chapter 3- Research Designs and Variables Correlational Design Longitudinal Studies Cross-Sectional Studies Experimental Design Independent Variable Dependent Variable Cause and Effect Random Assignment Extraneous Variables Internal Validity Levels of Measurement Nominal Variable Ordinal Variable Interval Variable Ratio Variable Why Do We Care? Summarizing Variables: Central Tendency Mode Median Mean Summarizing Variables: Variability Range Standard Deviation SPSS: Summarizing Variables Nominal Data Ordinal Data Interval and Ratio Data Summary Review of Terms Practice Items Reference Chapter 4- Learning About a Population From a Sample Selecting a Sample Random Sampling Cluster Sampling Stratified Random Sampling Convenience Sampling Bias in a Sample Inferential Statistics Sampling Error Probability Hypothesis Testing Significance p-values and Effect Size Power and Sample Size Degrees of Freedom Summary Review of Terms Practice Items Section II- Categorical Variables and Simple Frequency Chapter 5- One Variable With Frequency Data Research Design: Categorizing Participants One-Way Chi Square With Equal Expected Frequencies SPSS: One-Way Chi Square With Equal Expected Frequencies Effect Size: Cohen's w APA Style for the One-Way Chi Square With Equal Expected Frequencies Power One-Way Chi Square With Unequal Expected Frequencies SPSS: One-Way Chi Square With Unequal Expected Frequencies APA Style for the One-Way Chi Square With Unequal Expected Frequencies Summary Review of Terms Practice Items References Chapter 6- Two Variables With Frequency Data Research Design: Two Categorical Variables Two-Way Chi Square: 2 x 3 Design Power SPSS: 2 x 3 Chi Square Effect Size: Contingency Coefficient and Cramer's V APA Style for the 2 x 3 Chi Square Two-Way Chi Square: 2 x 2 Design Effect Size: Phi Coefficient SPSS: 2 x 2 Chi Square APA Style for the 2 x 2 Chi Square Summary Review of Terms Practice Items References Section III- Research Without Grouping Chapter 7- Examining Relationships Pearson's r: Seeking a Relationship SPSS: Pearson's r (Seeking a Relationship) Two-Tailed Test One-Tailed Test Power Graphs as Figures: Scatterplot APA Style for Pearson's r: Correlational Design Pearson's r: Seeking Cause and Effect Previewing Data With a Scatterplot SPSS: Pearson's r (Seeking Cause and Effect) Effect Size: Coefficient of Determination APA Style for Pearson's r: Experimental Design Inaccurate Pearson's r When Pearson's r Falsely Shows No Relationship Outliers That Weaken Pearson's r Nonlinear Relationship Restriction of Range When Pearson's r Falsely Shows a Relationship Restriction of Range on a Curvilinear Relationship Outliers That Strengthen Pearson's r Summary Review of Terms Practice Items References Chapter 8- Scale Development Pearson's r and Reliability of Measures Test-Retest Reliability Alternate-Forms Reliability Split-Half Reliability Cronbach's Alpha and Reliability of Measures SPSS: Scoring and Interpreting Measures Reverse Scoring Items Cronbach's Alpha on SPSS Scoring a Measure Reliability With Subjective Measures: Interrater Reliability Pearson's r and Validity Face Validity Content Validity Convergent Construct Validity Discriminant Construct Validity Predictive Validity Summary Review of Terms Practice Items References Chapter 9- Prediction Prediction and Correlation Linear Regression: Prediction Using One Predictor Correlation First Linear Regression Error in Predictions SPSS: Linear Regression Effect Size: Cohen's f 2 APA Style for Linear Regression Power Multiple Linear Regression: Prediction With Two Predictors SPSS: Multiple Linear Regression APA Style for Multiple Linear Regression Summary Review of Terms Practice Items References Section IV- Grouped Designs With Independent Samples Chapter 10- One Variable With Two Independent Groups Research Design: One IV With Two Levels SPSS: Independent-Samples t-test With an IV Directional Hypothesis Effect Size: Cohen's d Confidence Intervals Power APA Style for the Independent-Samples t-test: Experimental Design Graphs as Figures: Bar Graph Outliers Using a Quasi-IV to Establish a Relationship SPSS: Independent-Samples t-test With a Quasi-IV APA Style for the Independent-Samples t-test: Correlational Design Summary Review of Terms Practice Items References Chapter 11- One Variable With More Than Two Independent Groups Research Design: One IV With More Than Two Levels SPSS: One-Way, Between-Groups ANOVA With an IV Effect Size: Eta Squared Post Hoc Comparisons Confidence Intervals Power APA Style for the One-Way, Between-Groups ANOVA: Experimental Design Analyzing a Quasi-IV With More Than Two Levels SPSS: One-Way, Between-Groups ANOVA With a Quasi-IV APA Style for the One-Way, Between-Groups ANOVA: Correlational Design Summary Review of Terms Practice Items References Section V- Grouped Designs With Related Samples Chapter 12- One Variable with Two Related Groups Testing the Same People Twice Problems With Testing the Same People Twice Practice Effect Fatigue Effect History Effect Maturation Solving Order Problems by Counterbalancing Avoiding Confounds Research Design: One IV With Two Related Groups SPSS: Related-Samples t-test (Experimental Design) Confidence Intervals Effect Size: Cohen's d APA Style for the Related-Samples t-test: Experimental Design Power Research Design: One Quasi-IV With Two Related Groups SPSS: Related-Samples t-test (Correlational Design) APA Style for the Related-Samples t-test: Correlational Design Research Design: Testing Different People (Matched Pairs) Matching Participants Matching in a Two-Condition Study The Matching Process SPSS: Matched-Pairs t-test APA Style for the Matched-Pairs t-test Summary Review of Terms Practice Items References Chapter 13- One Variable With Repeated Measures: More Than Two Groups Research Design: One IV With Repeated Measures SPSS: One-Way, Repeated-Measures ANOVA (Experimental Design) Sphericity Effect Size: Eta Squared Confidence Intervals Power APA Style for the One-Way, Repeated-Measures ANOVA: Experimental Design Research Design: One Quasi-IV With Repeated Measures SPSS: One-Way, Repeated-Measures ANOVA (Correlational Design) APA Style for the One-Way, Repeated-Measures ANOVA: Correlational Design Summary Review of Terms Practice Items References Section VI- Advanced Design Chapter 14- Two Variables With Independent Samples Research Design: Two IVs With Independent Samples SPSS: Two-Way, Between-Groups ANOVA (No Significant Interaction) Effect Size: Eta Squared Post Hoc for a Main Effect Confidence Intervals Power Graphing a Main Effect APA Style for Two-Way, Between-Groups ANOVA With Main Effects Research Design: One IV and One Quasi-IV With Independent Groups SPSS: Two-Way, Between-Groups ANOVA (Significant Interaction) Examining the Interaction Post Hoc for an Interaction Graphing an Interaction APA Style for the Two-Way, Between-Groups ANOVA With an Interaction Summary Review of Terms Practice Items References Appendices Appendix A- Power Analysis Table Appendix B- Graphing in Excel Scatterplots Bar Graphs Line Graphs Interaction Graphs Appendix C- APA-Style Manuscript Guidelines Key Elements in APA-Style Writing The Basics Title Page Abstract Introduction Method Results Discussion References Tables, Figures, and Appendices Common Mistakes and Tips for Writing Example Paper With Comments Example Paper Without Comments Appendix D- Selected Answers to Practice Items Appendix E- Glossary of Terms Index