Introduction to Statistics in Criminal Justice and Criminology

About the Authors xiii Acknowledgements xv 1 Introduction 1 1.1 Statistics 1 1.2 Types of Statistics: Descriptive and Inferential 1 1.3 Basic Statistical Concepts and Terminology 2 1.4 Dependent and Independent Variables 10 1.5 Practical Application of Statistics 11 1.6 Introduction to SAS 11 1.7 Summary 12 1.8 Exercises 12 1.9 Answers to Exercises 14 2 Organizing and Describing Data 17 2.1 The Jail Report 17 2.2 Organizing and Describing Data 17 2.3 Frequency Distributions 18 2.4 Visual Techniques 27 2.5 Properties of Distributions 37 2.6 Summary 41 2.7 Exercises 42 2.8 Answers to Exercises 43 3 Comparative Statistics 48 3.1 Re-electing the County Sheriff 48 3.2 Trend Analyses 54 3.3 Summary 61 3.4 Importing Data from a Database in SAS 62 3.5 Exercises 62 3.6 Answers to Exercises 65 4 Descriptive Statistics: Measures of Central Tendency and Variability 69 4.1 Analysis of Domestic Violence Cases 69 4.2 Measures of Central Tendency 69 4.3 Central Tendency 70 4.4 The Mean 70 4.5 The Median 75 4.6 The Mode 76 4.7 When to Use Measures of Central Tendency: A FinalWord 83 4.8 Characteristics of the Mean and Median 84 4.9 Variability 85 4.10 The Range 86 4.11 Measures of Deviation 87 4.12 Variance 87 4.13 Standard Deviation 88 4.14 Calculating Central Tendencies and Variability in SAS 90 4.15 Summary 93 4.16 Exercises 93 4.17 Answers to Exercises 95 5 Normal Distributions 98 5.1 Theoretical Distributions 98 5.1.1 Characterizing Shapes 98 5.2 Normal Distribution PDF 99 5.3 Binomial Distribution PMF 100 5.4 The Standard Normal Distribution 104 5.5 Properties of Z-Scores 106 5.6 Summary 116 5.7 Exercises 116 5.8 Answers to Exercises 117 6 Hypothesis Testing: z- and t-Tests 119 6.1 Introduction 119 6.2 Hypothesis Testing, One Sample z 120 6.3 Hypothesis Testing, One Sample t 131 6.4 Summary 143 6.5 Exercises 144 6.6 Answers to Exercises 145 7 Analyzing Categorical Data: Chi-Square Test 152 7.1 Comparing Proportions 152 7.2 Comparing Proportions – Two Samples 155 7.3 The Chi-Square Test 156 7.4 Summary 166 7.5 Exercises 166 7.6 Answers to Exercises 167 8 Correlation Coefficient 176 8.1 Relationships Between Variables 176 8.2 Interpreting the Meaning and Significance of r 185 8.3 Summary 189 8.4 Exercises 193 8.5 Answers to Exercises 193 9 Linear Regression and Prediction 196 9.1 The Concept of Prediction 196 9.2 Basic Assumptions and Terminology 197 9.3 Linear Regression Using SAS 203 9.4 Multiple Linear Regression 211 9.5 Summary 218 9.6 Exercises 218 9.7 Answers to Exercises 219 10 Analysis of Variance 223 10.1 Introduction 223 10.2 A Return to Variance 224 10.3 Steps in Hypothesis Testing 229 10.4 ANOVA in SAS 237 10.5 Summary 239 10.6 Exercises 239 10.7 Answers to Exercises 241 11 Survival Analysis 249 11.1 Introduction 249 11.2 Survival Function 250 11.3 Summary 263 11.4 Exercises 263 11.5 Answers to Exercises 265 Appendices 268 Index 295