Interpreting and Using Statistics in Psychological Research

A practical introduction to statistical analysis by this award-winning teacher, helping students to make clear connections between statistics and the real world.

A practical introduction to statistical analysis by this award-winning teacher, helping students to make clear connections between statistics and the real world.

PrefaceAcknowledgmentsAbout the AuthorChapter 1- Why Do I Have to Learn Statistics? The Value of Statistical Thinking in Life Statistical Thinking and Everyday Life Failing to Use Information About Probability Availability heuristic Representativeness heuristic Misunderstanding Connections Between Events Illusory correlations Gambler's fallacy Goals of Research Goal: To Describe Goal: To Predict Goal: To Explain Goal: To Apply Statistical Thinking: Some Basic Concepts Parameters Versus Statistics Descriptive Statistics Versus Inferential Statistics Sampling Error Chapter Application Questions Questions for Class DiscussionChapter 2- Basics of Quantitative Research: Variables, Scales of Measurement, and an Introduction to the Statistical Package for the Social Sciences (SPSS) The Study Variables Operational Definitions Measurement Reliability and Validity Scales of Measurement: How We Measure Variables Nominal Data Ordinal Data Interval and Ratio (Scale) Data Discrete Versus Continuous Variables The Basics of SPSS Variable View Data View Chapter Application Questions Questions for Class DiscussionChapter 3- Describing Data With Frequency Distributions and Visual Displays The Study Frequency Distributions Frequency Distribution Tables Frequency Distribution Graphs Common Visual Displays of Data in Research Bar Graphs Scatterplots Line Graphs Using SPSS to Make Visual Displays of Data Making a Bar Graph Making a Scatterplot Making a Line Graph Chapter Application Questions Questions for Class DiscussionChapter 4- Making Sense of Data: Measures of Central Tendency and Variability Measures of Central Tendency Three Measures of Central Tendency Mean Median Mode Reporting the measures of central tendency in research Choosing a Measure of Central Tendency Consideration 1: Outliers in the data Consideration 2: Skewed data distributions Consideration 3: A variable's scale of measurement Consideration 4: Open-ended response ranges Measures of Central Tendency and SPSS Measures of Variability What Is Variability? Why Should We Care About Variability? Three Measures of Variability Range Variance Standard deviation Reporting variability in research Measures of Variability and SPSS Chapter Application Questions Questions for Class DiscussionChapter 5- Determining "High" and "Low" Scores: The Normal Curve, z Scores, and Probability Types of Distributions Normal Distributions Skewed Distributions Standardized Scores (z Scores) z Scores, the Normal Distribution, and Percentile Ranks Locating Scores Under the Normal Distribution Percentile Ranks z Scores and SPSS Chapter Application Questions Questions for Class DiscussionChapter 6- Drawing Conclusions From Data: Descriptive Statistics, Inferential Statistics, and Hypothesis Testing Basics of Null Hypothesis Testing Null Hypotheses and Research Hypotheses Alpha Level and the Region of Null Hypothesis Rejection Gathering Data and Testing the Null Hypothesis Making a Decision About the Null Hypothesis Type I Errors, Type II Errors, and Uncertainty in Hypothesis Testing The z Test A Real-World Example of the z Test Ingredients for the z Test Using the z Test for a Directional (One-Tailed) Hypothesis Using the z Test for a Nondirectional (Two-Tailed) Hypothesis One-Sample t Test A Real-Word Example of the One-Sample t Test Ingredients for the One-Sample t Test Using the One-Sample t Test for a Directional (One-Tailed) Hypothesis Using the One-Sample t Test for a Nondirectional (Two-Tailed) Hypothesis One-Sample t Test and SPSS Statistical Power and Hypothesis Testing Chapter Application Questions Questions for Class DiscussionChapter 7- Comparing Two Group Means: The Independent Samples t Test Conceptual Understanding of the Statistical Tool The Study The Tool Ingredients Hypothesis from Kasser and Sheldon (2000) Interpreting the Tool Assumptions of the tool Testing the null hypothesis Extending our null hypothesis test Using Your New Statistical Tool Hand-Calculating the Independent Samples t Test Step 1: State hypotheses Step 2: Calculate the mean for each of the two groups Step 3: Calculate the standard error of the difference between the means Step 4: Calculate the t test statistic Step 5: Determine degrees of freedom (dfs) Step 6: Locate the critical value Step 7: Make a decision about the null hypothesis Step 8: Calculate an effect size Step 9: Determine the confidence interval Independent Samples t Test and SPSS Establishing your spreadsheet Running your analyses What am I looking at? Interpreting your SPSS output Chapter Application Questions Questions for Class DiscussionChapter 8- Comparing Two Repeated Group Means: The Paired Samples t Test Conceptual Understanding of the Tool The Study The Tool Ingredients Hypothesis from Stirling et al. (2014) Interpreting the Tool Testing the null hypothesis Extending our null hypothesis test Assumptions of the tool Using Your New Statistical Tool Hand-Calculating the Paired Samples t Test Step 1: State hypotheses Step 2: Calculate the mean difference score Step 3: Calculate the standard error of the difference scores Step 4: Calculate the t test statistic Step 5: Determine degrees of freedom (dfs) Step 6: Locate the critical value Step 7: Make a decision about the null hypothesis Step 8: Calculate an effect size Step 9: Determine the confidence interval Paired Samples t Test and SPSS Establishing your spreadsheet Running your analyses What am I looking at? Interpreting your SPSS output Chapter Application Questions Questions for Class DiscussionChapter 9- Comparing Three or More Group Means: The One-Way, Between-Subjects Analysis of Variance (ANOVA) Conceptual Understanding of the Tool The Study The Tool Ingredients Assumptions of the tool Hypothesis from Eskine (2012) Interpreting the Tool Testing the null hypothesis Extending our null hypothesis test Going beyond the F ratio: Post hoc tests Using Your New Statistical Tool Hand-Calculating the One-Way, Between-Subjects ANOVA Step 1: State hypotheses Step 2: Calculate the mean for each group Step 3: Calculate the sums of squares (SSs) Total Sums of Squares (SStotal) Within-Groups Sums of Squares (SSwithin-groups) Between-Groups Sums of Squares (SSbetween-groups) Step 4: Determine degrees of freedom (dfs) Total Degrees of Freedom (dftotal) Within-Groups Degrees of Freedom (dfwithin-groups) Between-Groups Degrees of Freedom (dfbetween-groups) Step 5: Calculate the mean squares (MSs) Step 6: Calculate your F ratio test statistic Step 7: Locate the critical value Step 8: Make a decision about the null hypothesis Step 9: Calculate an effect size Step 10: Perform post hoc tests One-Way Between-Subjects ANOVA and SPSS Establishing your spreadsheet Running your analysis What am I looking at? Interpreting your SPSS output Chapter Application Questions Questions for Class DiscussionChapter 10- Comparing Three or More Repeated Group Means: The One-Way, Repeated-Measures Analysis of Variance (ANOVA) Conceptual Understanding of the Tool The Study The Tool Between-subjects versus repeated-measures ANOVAs Assumptions of the tool Hypothesis from Bernard et al. (2014) Interpreting the Tool Testing the null hypothesis Extending our null hypothesis test Going beyond the F ratio: Post hoc tests Using Your New Statistical Tool Hand-Calculating the One-Way, Repeated-Measures ANOVA Step 1: State the hypothesis Step 2: Calculate the mean for each group Step 3: Calculate the sums of squares (SSs) Total Sums of Squares (SStotal) Between Sums of Squares (SSbetween) Error Sums of Squares (SSerror) Step 4: Determine degrees of freedom (dfs) Total Degrees of Freedom (dftotal) Between Degrees of Freedom (dfbetween) Error Degrees of Freedom (dferror) Step 5: Calculate the mean squares (MSs) Step 6: Calculate your F ratio test statistic Step 7: Locate the critical value Step 8: Make a decision about the null hypothesis Step 9: Calculate an effect size Step 10: Perform post hoc tests One-Way, Repeated-Measures ANOVA and SPSS Establishing your spreadsheet Running your analysis What am I looking at? Interpreting your SPSS output Chapter Application Questions Questions for Class DiscussionChapter 11- Analyzing Two or More Influences on Behavior: Factorial Designs for Two Between-Subjects Factors Conceptual Understanding of the Tool The Study The Tool Factorial notation Main effects and interactions Hypothesis from Troisi and Gabriel (2011) Interpreting the Tool Testing the null hypothesis Extending the null hypothesis tests Dissecting a statistically significant interaction Using Your New Statistical Tool Hand-Calculating the Two-Way, Between-Subjects ANOVA Step 1: State the hypotheses Step 2: Calculate the mean for each group and the marginal means Step 3: Calculate the sums of squares (SSs) Total Sums of Squares (SStotal) Within-Groups Sums of Squares (SSwithin-groups) Between-Groups Sums of Squares (SSbetween-groups) Step 4: Determine degrees of freedom (dfs) Total Degrees of Freedom (dftotal) Within-Groups Degrees of Freedom (dfwithin-groups) Between-Groups Degrees of Freedom (dfbetween-groups) Step 5: Calculate the mean squares (MSs) Step 6: Calculate your F ratio test statistics Step 7: Locate the critical values Step 8: Make a decision about each null hypothesis Step 9: Calculate the effect sizes Step 10: Perform follow-up tests Two-Way, Between-Subjects ANOVA and SPSS Establishing your spreadsheet Running your analysis What am I looking at? Interpreting your SPSS output Dissecting interactions in SPSS Chapter Application Questions Questions for Class DiscussionChapter 12- Determining Patterns in Data: Correlations Conceptual Understanding of the Tool The Study The Tool Types (directions) of correlations Strength of correlations Assumptions of the Pearson correlation Uses for correlations Use 1: Studying naturally occurring relationships Use 2: Basis for predictions Use 3: Establishing measurement reliability and validity Hypotheses from Clayton et al. (2013) Interpreting the Tool Testing the null hypothesis Cautions in interpreting correlations Caution 1: Don't confuse type (direction) and strength of a correlation Caution 2: Range restriction Caution 3: "Person-who" thinking Caution 4: Curvilinear relationships Caution 5: Spurious correlations Using Your New Statistical Tool Hand-Calculating the Person Correlation Coefficient (r) Step 1: State hypotheses Step 2: For both variables, find each participant's deviation score and then multiply them together Step 3: Sum the products in step 2 Step 4: Calculate the sums of squares for both variables Step 5: Multiply the two sums of squares and then take the square root Step 6: Calculate the correlation coefficient (r) test statistic Step 7: Locate the critical value Step 8: Make a decision about the null hypothesis The Pearson Correlation (r) and SPSS Establishing your spreadsheet Running your analysis What am I looking at? Interpreting your SPSS output Chapter Application Questions Questions for Class DiscussionChapter 13- Predicting the Future: Univariate and Multiple Regression Univariate Regression Ingredients Hand-Calculating a Univariate Regression Step 1: Calculate the slope of the line (b) Step 2: Calculate the y-intercept (a) Step 3: Make predictions Univariate Regression and SPSS Running your analysis What am I looking at? Interpreting your SPSS output Multiple Regression Understanding Multiple Regression in Research Multiple Regression and SPSS Establishing your spreadsheet Running your analysis What am I looking at? Interpreting your SPSS output Chapter Application Questions Questions for Class DiscussionChapter 14- When We Have Exceptions to the Rules: Nonparametric Tests Chi-Square (x2) Tests Chi-Square (x2) Goodness-of-Fit Test Hand-calculating the ?2 goodness-of-fit test Step 1: State hypotheses Step 2: Determine degrees of freedom (dfs) Step 3: Calculate the x2 test statistic Step 4: Find the critical value and make a decision about the null hypothesis x2 goodness-of-fit test and SPSS Establishing your spreadsheet Running your analysis What am I looking at? Interpreting your SPSS output Chi-Square (x2) Test of Independence Hand-calculating the x2 test of independence Step 1: State hypotheses Step 2: Determine degrees of freedom (dfs) Step 3: Calculate expected frequencies Step 4: Calculate the x2 test statistic Step 5: Find the critical value and make a decision about the null hypothesis Step 6: Calculate an effect size x2 test for independence and SPSS Establishing your spreadsheet Running your analysis What am I looking at? Interpreting your SPSS output Spearman Rank-Order Correlation Coefficient Hand-Calculating the Spearman Rank-Order Correlation Step 1: State the hypothesis Step 2: Calculate the difference (D) score between each pair of rankings Step 3: Square and sum the difference scores in step 2 Step 4: Calculate the Spearman correlation coefficient (rs) test statistic Step 5: Locate the critical value and make a decision about the null hypothesis Spearman's Rank-Order Correlation and SPSS Establishing your spreadsheet Running your analysis What am I looking at? Interpreting your SPSS output Mann-Whitney U Test Hand-Calculating the Mann-Whitney U Test Step 1: State hypotheses Step 2: Calculate the ranks for categories being compared Step 3: Sum the ranks for each category Step 4: Find the U for each group Step 5: Locate the critical value and make a decision about the null hypothesis Mann-Whitney U Test and SPSS Establishing your spreadsheet Running your analysis What am I looking at? Interpreting your SPSS output Chapter Application Questions Questions for Class DiscussionChapter 15- Bringing It All Together: Using Your Statistical Toolkit Deciding on the Appropriate Tool: Six Examples Study 1: "Waiting for Merlot: Anticipatory Consumption of Experiential and Material Purchases Study 2: "Evaluations of Sexy Women in Low- and High-Status Jobs" Study 3: "Evil Genius? How Dishonesty Can Lead to Greater Creativity" Study 4: "Differential Effects of a Body Image Exposure Session on Smoking Urge Between Physically Active and Sedentary Female Smokers" Study 5: "Texting While Stressed: Implications for Students' Burnout, Sleep, and Well-Being" Study 6: "How Handedness Direction and Consistency Relate to Declarative Memory Task Performance" Using Your Toolkit to Identify Appropriate Statistical Tools Study 7: "Borderline Personality Disorder: Attitudinal Change Following Training" Study 8: "Effects of Gender and Type of Praise on Task Performance Among Undergraduates" Study 9: "Please Respond ASAP: Workplace Telepressure and Employee Recovery" Answers to Studies 7, 8, and 9Appendices: Statistical TablesGlossaryReferencesIndex