A Note to the Student: Why I Wrote This Book 

xvii  
Acknowledgments 

xviii  
And Now, About the 2nd Edition 

xix  

PART I Yippee! I'm in Statistics 


1  (16) 

Statistics or Sadistics? It's Up to You 


5  (12) 


5  (1) 

A FiveMinute History of Statistics 


6  (2) 

Statistics: What It Is (and Isn't) 


8  (2) 

What Are Descriptive Statistics? 


8  (1) 

What Are Inferential Statistics? 


9  (1) 


10  (1) 

What Am I Doing in a Statistics Class? 


10  (2) 

Ten Ways to Use This Book (and Learn Statistics at the Same Time!) 


12  (2) 


14  (1) 


15  (1) 


15  (1) 


15  (1) 


16  (1) 

PART II Σigma Freud and Descriptive Statistics 


17  (84) 

Means to an End: Computing and Understanding Averages 


19  (15) 


20  (1) 


21  (2) 

Computing a Weighted Mean 


22  (1) 


23  (3) 


26  (1) 


27  (1) 


28  (1) 


28  (1) 

Using the Computer and Computing Descriptive Statistics 


29  (3) 


31  (1) 


32  (1) 


32  (1) 

Answers to Practice Questions 


33  (1) 

Vive la Difference: Understanding Variability 


34  (14) 

Why Understanding Variability Is Important 


34  (1) 


35  (1) 

Computing the Standard Deviation 


36  (5) 

Why n  1? What's Wrong With Just n? 


40  (1) 


41  (1) 


41  (1) 


42  (1) 

The Standard Deviation Versus the Variance 


42  (1) 

Using the Computer to Compute Measures of Variability 


43  (2) 


44  (1) 


45  (1) 


46  (1) 

Answers to Practice Questions 


47  (1) 

A Picture Really Is Worth a Thousand Words 


48  (29) 


48  (1) 

Ten Ways to a Great Figure (Eat Less and Exercise More?) 


49  (1) 

First Things First: Creating a Frequency Distribution 


50  (2) 

The Classiest of Intervals 


51  (1) 

The Plot Thickens: Creating a Histogram 


52  (7) 


55  (1) 

The Next Step: A Frequency Polygon 


56  (1) 


57  (2) 

Fat and Skinny Frequency Distributions 


59  (5) 


59  (1) 


60  (1) 


61  (1) 


62  (2) 

Other Cool Ways to Chart Data 


64  (3) 


64  (1) 


65  (1) 


65  (1) 


66  (1) 

Using the Computer to Illustrate Data 


67  (6) 

Creating a Histogram Graph 


67  (2) 


69  (1) 


70  (2) 


72  (1) 


73  (1) 


74  (1) 

Answers to Practice Questions 


75  (2) 

Ice Cream and Crime: Computing Correlation Coefficients 


77  (24) 

What Are Correlations All About? 


77  (2) 

Types of Correlation Coefficients: Flavor 1 and Flavor 2 


78  (1) 


79  (2) 

Computing a Simple Correlation Coefficient 


81  (7) 

A Visual Picture of a Correlation: The Scatterplot 


83  (4) 

Bunches of Correlations: The Correlation Matrix 


87  (1) 

Understanding What the Correlation Coefficient Means 


88  (1) 


88  (1) 

A Determined Effort: Squaring the Correlation Coefficient 


89  (3) 

As More Ice Cream Is Eaten . . . the Crime Rate Goes Up (or Association vs. Causality) 


90  (2) 


92  (1) 

Using the Computer to Compute a Correlation Coefficient 


93  (2) 


94  (1) 

Creating an SPSS Scatterplot (or Scattergram or Whatever) 


95  (1) 


96  (1) 


97  (2) 

Answers to Practice Questions 


99  (2) 

PART III Taking Chances for Fun and Profit 


101  (38) 

Hypotheticals and You: Testing Your Questions 


103  (15) 

So You Want to Be a Scientist . . . 


103  (2) 


104  (1) 


105  (2) 

The Purposes of the Null Hypothesis 


106  (1) 


107  (5) 

The Nondirectional Research Hypothesis 


108  (1) 

The Directional Research Hypothesis 


109  (2) 

Some Differences Between the Null Hypothesis and the Research Hypothesis 


111  (1) 

What Makes a Good Hypothesis? 


112  (3) 


115  (1) 


116  (1) 

Answers to Practice Questions 


117  (1) 

Are Your Curves Normal? Probability and Why It Counts 


118  (21) 


118  (1) 

The Normal Curve (a.k.a. the BellShaped Curve) 


119  (7) 


120  (2) 


122  (4) 

Our Favorite Standard Score: The z Score 


126  (9) 


129  (3) 

What z Scores Really Represent 


132  (2) 

Hypothesis Testing and z Scores: The First Step 


134  (1) 

Using the Computer to Compute z Scores 


135  (1) 


136  (1) 


137  (1) 

Answers to Practice Questions 


138  (1) 

PART IV Significantly Different: Using Inferential Statistics 


139  (174) 

Significantly Significant: What It Means for You and Me 


141  (19) 

The Concept of Significance 


141  (7) 


142  (2) 

The World's Most Important Table (for This Semester Only) 


144  (1) 


145  (1) 


146  (2) 

Significance Versus Meaningfulness 


148  (2) 

An Introduction to Inferential Statistics 


150  (3) 


150  (1) 

How to Select What Test to Use 


151  (2) 

Here's How to Use the Chart 


153  (1) 

An Introduction to Tests of Significance 


153  (4) 

How a Test of Significance Works: The Plan 


154  (1) 

Here's the Picture That's Worth a Thousand Words 


155  (2) 


157  (1) 


158  (1) 

Answers to Practice Questions 


159  (1) 

t(ea) for Two: Tests Between the Means of Different Groups 


160  (19) 

Introduction to the t Test for Independent Samples 


160  (3) 

The Path to Wisdom and Knowledge 


161  (2) 

Computing the Test Statistic 


163  (4) 

So How Do I Interpret t(58) = .14, p > .05? 


167  (1) 

Special Effects: Are Those Differences for Real? 


167  (4) 

Computing and Understanding the Effect Size 


169  (2) 

A Very Cool Effect Size Calculator 


171  (1) 

Using the Computer to Perform a t Test 


171  (4) 

What the SPSS Output Means 


175  (1) 


175  (1) 


176  (1) 

Answers to Practice Questions 


177  (2) 

t(ea) for Two (Again): Tests Between the Means of Related Groups 


179  (14) 

Introduction to the t Test for Dependent Samples 


179  (3) 

The Path to Wisdom and Knowledge 


180  (2) 

Computing the Test Statistic 


182  (4) 

So How Do I Interpret t(24) = 2.45, p < .05? 


185  (1) 

Using the Computer to Perform a t Test 


186  (4) 

What the SPSS Output Means 


187  (3) 


190  (1) 


191  (1) 

Answers to Practice Questions 


192  (1) 

Two Groups Too Many? Try Analysis of Variance 


193  (19) 

Introduction to Analysis of Variance 


193  (4) 

The Path to Wisdom and Knowledge 


194  (1) 

Different Flavors of ANOVA 


194  (3) 

Computing the Test Statistic 


197  (8) 

So How Do I Interpret F(2,27) = 8.80, p < .05? 


204  (1) 

Using the Computer to Compute the F Ratio 


205  (3) 

What the SPSS Output Means 


206  (2) 


208  (2) 


210  (1) 

Answers to Practice Questions 


211  (1) 

Two Too Many Factors: Factorial Analysis of Variance 


212  (16) 

Introduction to Factorial Analysis of Variance 


212  (4) 

The Path to Wisdom and Knowledge 


213  (1) 


214  (2) 

The Main Event: Main Effects in Factorial ANOVA 


216  (2) 

Even More Interesting: Interaction Effects 


218  (2) 


220  (1) 

Computing the Test Statistic 


220  (5) 

What the SPSS Output Means 


225  (1) 


225  (1) 


226  (1) 

Answers to Practice Questions 


227  (1) 

Cousins or Just Good Friends? Testing Relationships Using the Correlation Coefficient 


228  (14) 

Introduction to Testing the Correlation Coefficient 


228  (3) 

The Path to Wisdom and Knowledge 


229  (2) 

Computing the Test Statistic 


231  (5) 

So How Do I Interpret r(27) = .393, p < .05? 


234  (1) 

Causes and Associations (Again!) 


235  (1) 

Significance Versus Meaningfulness (Again, Again!) 


235  (1) 

Using the Computer to Compute a Correlation Coefficient (Again) 


236  (2) 

What the SPSS Output Means 


238  (1) 


238  (1) 


239  (1) 

Answers to Practice Questions 


240  (2) 

Predicting Who'll Win the Super Bowl: Using Linear Regression 


242  (19) 

What Is Prediction All About? 


242  (2) 


244  (4) 

Drawing the World's Best Line (for Your Data) 


248  (3) 

How Good Is Our Prediction? 


250  (1) 

Using the Computer to Compute the Regression Line 


251  (4) 

What the SPSS Output Means 


254  (1) 

The More Predictors the Better? Maybe . . . 


255  (2) 

The Big Rule When It Comes to Using Multiple Predictor Variables 


256  (1) 


257  (1) 


258  (2) 

Answers to Practice Questions 


260  (1) 

What to Do When You're Not Normal: ChiSquare and Some Other Nonparametric Tests 


261  (12) 

Introduction to Nonparametric Statistics 


261  (1) 

Introduction to OneSample ChiSquare 


262  (1) 

Computing the ChiSquare Test Statistic 


263  (4) 

So How Do I Interpret Χ2(2) = 20.6, p < .05? 


267  (1) 

Using the Computer to Perform a ChiSquare Test 


267  (2) 

What the SPSS Output Means 


269  (1) 

Other Nonparametric Tests You Should Know About 


269  (1) 


270  (1) 


271  (1) 

Answers to Practice Questions 


272  (1) 

Just the Truth: An Introduction to Understanding Reliability and Validity 


273  (24) 

An Introduction to Reliability and Validity 


273  (2) 

What's Up With This Measurement Stuff? 


274  (1) 

All About Measurement Scales 


275  (2) 

A Rose by Any Other Name: The Nominal Level of Measurement 


275  (1) 

Any Order Is Fine With Me: The Ordinal Level of Measurement 


276  (1) 

1 + 1 = 2: The Interval Level of Measurement 


276  (1) 

Can Anyone Have Nothing of Anything? The Ratio Level of Measurement 


276  (1) 


277  (1) 

ReliabilityDoing It Again Until You Get It Right 


277  (7) 

Test ScoresTruth or Dare 


278  (1) 

Observed Score = True Score + Error Score 


278  (1) 

Different Types of Reliability 


279  (5) 

Using the Computer to Calculate Cronbach's Alpha 


284  (5) 


286  (1) 

How Big Is Big? Interpreting Reliability Coefficients 


287  (1) 


288  (1) 

ValidityWhoa! What Is the Truth? 


289  (5) 

Different Types of Validity 


289  (4) 


293  (1) 

Validity and Reliability: Really Close Cousins 


294  (1) 


294  (1) 


295  (1) 

Answers to Practice Questions 


296  (1) 

Some Other (Important) Statistical Procedures You Should Know About 


297  (6) 

Multivariate Analysis of Variance 


297  (1) 

Repeated Measures Analysis of Variance 


298  (1) 


299  (1) 


299  (1) 


300  (1) 


301  (1) 

Structural Equation Modeling 


301  (1) 


302  (1) 

A Statistical Software Sampler 


303  (10) 

Selecting the Perfect Statistics Software 


304  (1) 


305  (7) 


306  (1) 


307  (1) 


307  (1) 


308  (1) 

SPSS: Mac, Windows, MSDOS, OS/2, UNIX, VMS, MVSVM/CMS 


309  (1) 


310  (1) 


310  (1) 


311  (1) 


312  (1) 

PART V Tons of Things You'll Want to Know and Remember 


313  (12) 

The Ten (or More) Best Internet Sites for Statistics Stuff 


315  (7) 

Tons and Tons of Resources 


315  (1) 


316  (1) 

Who's Who and What's Happened 


317  (1) 


317  (1) 


318  (1) 


318  (1) 

More and More and More and More Resources 


319  (1) 


319  (1) 

How About Studying Statistics in Stockholm? 


319  (1) 

More and More and More ResourcesAgain! 


320  (1) 

Online Statistical Teaching Materials 


320  (1) 

More and More and More Stuff 


321  (1) 

The Ten Commandments of Data Collection 


322  (3) 

Appendix A: SPSS in Less Than 30 Minutes 


325  (28) 


327  (2) 


327  (2) 

The SPSS Toolbar and Status Bar 


329  (1) 


330  (2) 

Using the F1 Function Key 


331  (1) 


332  (2) 


332  (1) 


333  (1) 


333  (1) 

Creating and Editing a Data File 


334  (6) 


335  (1) 

Custom Defining Variables: Using the Variable View Window 


335  (2) 


337  (1) 


338  (2) 


340  (1) 


340  (1) 

Printing an SPSS Data File 


340  (1) 

Printing a Selection From an SPSS Data File 


341  (1) 


341  (3) 


341  (2) 


343  (1) 


344  (4) 


344  (4) 


348  (4) 

Frequencies and Crosstab Tables 


348  (2) 

Applying the Independent Samples t Test 


350  (2) 


352  (1) 


353  (16) 

Table B1: Areas Beneath the Normal Curve 


353  (4) 

Table B2: t Values Needed for Rejection of the Null Hypothesis 


357  (3) 

Table B3: Critical Values for Analysis of Variance or F Test 


360  (4) 

Table B4: Values of the Correlation Coefficient Needed for Rejection of the Null Hypothesis 


364  (2) 

Table B5: Critical Values for the ChiSquare Test 


366  (3) 


369  (13) 


370  (1) 


370  (1) 


371  (1) 


371  (1) 


372  (1) 


373  (1) 


374  (1) 


375  (2) 


377  (1) 


377  (1) 


378  (2) 


380  (2) 
Glossary 

382  (9) 
Index 

391  (12) 
About the Author 

403  