Preface 

xi  

Why the Criminal Justice Researcher Uses Statistics 


1  (22) 

The Nature of Criminal Justice Research 


1  (5) 

Major Data Sources in Criminology and Criminal Justice 


6  (1) 


7  (1) 

The Stages of Criminal Justice Research 


8  (1) 

Using Series of Numbers to Do Criminal Justice Research 


9  (4) 


13  (5) 


18  (1) 


19  (1) 


19  (4) 

Looking at the Larger Picture A Student Survey 


21  (2) 
PART ONE Description 

23  (98) 


25  (48) 

Frequency Distributions of Nominal Data 


25  (1) 


26  (1) 

Proportions and Percentages 


27  (1) 


28  (3) 

Simple Frequency Distributions of Ordinal and Interval Data 


31  (1) 

Grouped Frequency Distributions of Interval Data 


32  (3) 


35  (2) 


37  (6) 

Dealing with Decimal Data 


43  (2) 


45  (1) 


46  (7) 


53  (14) 


67  (1) 


68  (1) 


68  (5) 

Measures of Central Tendency 


73  (22) 


73  (1) 


74  (1) 


75  (4) 

Taking One Step at a Time 


79  (1) 

Comparing the Mode, Median, and Mean 


80  (4) 

Obtaining the Mode, Median, and Mean from a Simple Frequency Distribution 


84  (3) 

Obtaining the Mode, Median, and Mean from a Grouped Frequency Distribution 


87  (2) 


89  (1) 


90  (1) 

StepbyStep Study Guide: Mode, Median, and Mean for Raw Scores 


90  (1) 


91  (4) 


95  (26) 


96  (1) 


97  (2) 

The Variance and Standard Deviation 


99  (4) 

The RawScore Formula for Variance and Standard Deviation 


103  (2) 

The Meaning of the Standard Deviation 


105  (3) 

Comparing Measures of Variability 


108  (1) 

Obtaining the Variance and Standard Deviation from a Simple Frequency Distribution 


109  (3) 

Obtaining the Variance and Standard Deviation from a Grouped Frequency Distribution 


112  (2) 


114  (1) 


114  (1) 

StepbyStep Study Guide: Variance and Standard Deviation for Raw Scores 


114  (1) 


115  (6) 

Looking at the Larger Picture Describing Data 


118  (3) 
PART TWO From Description to Decision Making 

121  (72) 

Probability and the Normal Curve 


123  (33) 


124  (3) 

Probability Distributions 


127  (4) 

The Normal Curve as a Probability Distribution 


131  (1) 

Characteristics of the Normal Curve 


131  (1) 

The Model and the Reality of the Normal Curve 


132  (2) 

The Area under the Normal Curve 


134  (6) 

Standard Scores and the Normal Curve 


140  (3) 

Finding Probability under the Normal Curve 


143  (4) 

Obtaining Percentile Ranks from the Normal Curve 


147  (4) 


151  (1) 


151  (1) 

StepbyStep Study Guide: Probability under the Normal Curve 


151  (1) 

StepbyStep Study Guide: Percentile Ranks from the Normal Curve 


151  (1) 


152  (4) 


156  (37) 


157  (4) 


161  (1) 

Sampling Distribution of Means 


162  (7) 

Standard Error of the Mean 


169  (1) 


170  (6) 


176  (7) 


183  (3) 


186  (1) 


186  (1) 

StepbyStep Study Guide: Confidence Interval for the Mean Using z 


186  (1) 

StepbyStep Study Guide: Confidence Interval for the Mean Usin t 


187  (1) 

StepbyStep Study Guide: Confidence Interval for the Proportion 


188  (1) 


188  (5) 

Looking at the Larger Picture Generalizing from Samples to Populations 


191  (2) 
PART THREE Decision Making 

193  (114) 

Testing Differences between Means 


195  (43) 

The Null Hypothesis: No Difference between Means 


197  (1) 

The Research Hypothesis: A Difference between Means 


198  (1) 

Sampling Distribution of Differences between Means 


198  (4) 

Testing Hypotheses with the Distribution of Differences between Means 


202  (4) 


206  (4) 

Standard Error of the Difference between Means 


210  (1) 

Testing the Difference between Means 


211  (4) 

Comparing the Same Sample Measured Twice 


215  (4) 

Two Sample Tests of Proportions 


219  (2) 


221  (7) 

Requirements for Testing the Difference between Means 


228  (1) 


229  (1) 


230  (1) 

StepbyStep Study Guide: Test of Differences between Means for Independent Groups 


230  (1) 

StepbyStep Study Guide: Test of Differences between Means for the Same Sample Measured Twice 


231  (1) 

StepbyStep Study Guide: Test of Differences between Proportions 


232  (1) 


232  (6) 


238  (25) 

The Logic of Analysis of Variance 


239  (2) 


241  (6) 


247  (2) 


249  (6) 

A Multiple Comparison of Means 


255  (2) 

Requirements for Using the F Ratio 


257  (1) 


258  (1) 


258  (1) 

StepbyStep Study Guide: Test of Differences between Means for Several Independent Groups Using Analysis of Variance 


259  (1) 


260  (3) 

Nonparametric Tests of Significance 


263  (44) 


264  (5) 


269  (19) 


288  (3) 


291  (3) 

KruskalWallis OneWay Analysis of Variance by Ranks 


294  (3) 


297  (1) 


298  (1) 

StepbyStep Study Guide: Test of Differences between Groups for NominalLevel Data Using ChiSquare 


298  (1) 

StepbyStep Study Guide: Test of Differences between Groups for OrdinalLevel Data Using the MannWhitney U Test 


299  (1) 

StepbyStep Study Guide: Test of Differences between Several Groups for OrdinalLevel Data Using the KruskalWallis Test 


299  (1) 


300  (7) 

Looking at the Larger Picture Testing for Differences 


305  (2) 
PART FOUR From Decision Making to Association 

307  (112) 


309  (25) 


309  (1) 


310  (1) 


311  (1) 

The Correlation Coefficient 


312  (1) 

Pearson's Correlation Coefficient 


313  (8) 

The Importance of Scatter Plots 


321  (2) 


323  (6) 


329  (1) 


329  (1) 

StepbyStep Study Guide: Testing the Strength of Association between IntervalLevel Variables Using Pearson's Correlation 


329  (1) 


330  (4) 


334  (26) 


335  (5) 

Interpreting the Regression Line 


340  (2) 


342  (4) 

Regression and Pearson's Correlation 


346  (1) 

Regression and Analysis of Variance 


347  (5) 


352  (2) 


354  (1) 


355  (1) 

StepbyStep Study Guide: Testing the Effect of an Independent Variable on a Dependent Variable Using Regression Analysis 


355  (1) 


356  (4) 

Nonparametric Measures of Correlation 


360  (32) 

Spearman's RankOrder Correlation Coefficient 


360  (7) 

Goodman's and Kruskal's Gamma 


367  (5) 

Correlation Coefficient for Nominal Data Arranged in a 2 X 2 Table 


372  (2) 

Correlation Coefficient for Nominal Data in Larger than 2 X 2 Tables 


374  (3) 


377  (3) 


380  (5) 


385  (1) 


385  (1) 

StepbyStep Study Guide: Testing the Strength of Association between OrdinalLevel Variables Using Spearman's RankOrder Correlation 


386  (1) 

StepbyStep Study Guide: Testing the Strength of Association between CrossTabulated, OrdinalLevel Variables Using Goodman's and Kruskal's Gamma 


386  (1) 


387  (5) 

Looking at the Larger Picture Measuring Association 


391  (1) 

Applying Statistical Procedures to Research Problems 


392  (27) 


394  (15) 


409  (10) 
APPENDIXES 

419  (33) 

Appendix A Selected Criminal Justice Sites on the World Wide Web 


421  (3) 

Appendix B A Review of Some Fundamentals of Mathematics 


424  (5) 


429  (16) 

Appendix D List of Formulas 


445  (7) 
Glossary 

452  (7) 
Answers to Problems 

459  (7) 
Index 

466  