Statistical Methods for the Information Professional : A Practical, Painless Approach to Understanding, Using, and Interpreting Statistics

List of Figures xi List of Tables xv Preface xvii Not Just Another Stats Book xvii Who Should Read this Book xviii How to Use this Book xviii Acknowledgments xxi Getting Started---Recognizing the Types of Data 1(8) Nominal Data 1(1) Ordinal Data 2(1) Interval Data 3(1) Ratio Data 4(1) Data Conversion 5(4) Avoiding Manual Calculations and Formula Manipulations---Using Software 9(6) Types of Software 9(1) Which Software to Select 10(1) How to Organize Data into a Computer File 11(1) How to Deal with Missing Data 12(3) First Look---Using Graphs to See the Characteristics of Data 15(10) Variety of Graphs 15(5) A Special Bar Graph---Histogram 20(5) Summarizing Messy Data into Neat Figures---Descriptive Statistics 25(20) Measures of Central Tendency 25(8) Mean---The Arithmetic Average 26(2) Median---The Middle Point 28(1) Mode---The Peak of the Histogram 29(2) When to Use Which Measure of Central Tendency---A Summary 31(2) Measures of Variability 33(5) Range 34(1) Interquartile Range (IQR) 35(1) Standard Deviation (SD) 35(3) Variance 38(1) When to Use Which Measure of Variability---A Summary 38(1) Tying Together Descriptive Statistics Measures---Examples 38(7) What Is Statistically Significant?---Basic Concepts of Inferential Statistics 45(22) Descriptive Statistics vs. Inferential Statistics 45(1) Population vs. Sample 46(1) Parameter vs. Statistic 46(1) Probability and Frequency Distribution 47(3) Normal Distribution 50(1) The Z Score 51(2) Standard Normal Distribution 53(1) Confidence Interval 54(5) Hypothesis Testing---Statistically Significant or Not 59(4) Errors of Statistical Testing---Type I and Type II Errors 63(4) How to Collect Data---Sampling Methods 67(8) Simple Random Sample 67(2) Systematic Sample 69(1) Stratified Sample 70(1) Sampling Bias 71(4) Examining Relationships for Nominal and Ordinal Data---Chi-Square Test 75(18) The Logic of the Chi-Square Test 75(3) Calculation of Expected Frequencies 78(2) Chi-Square Score 80(1) Chi-Square Table 81(2) Examining the Pattern of the Relationship 83(1) An Example of Using Software to Carry Out a Chi-Square Test 84(4) Requirements for Using Chi-Square Test 88(5) Examining Relationships for Interval and Ratio Data---Correlation and Regression 93(18) Types of Correlation 94(1) Using A Scatter Plot a View the Pattern of Relationship 95(1) Measuring the Strength of a Relationship---Pearson 1 95(3) Testing the Significance of Pearson 1 98(2) Correlation and Causation 100(2) Regression Equation and Regression Line 102(5) Prediction 107(2) Requirements for Doing Correlation of Regression 109(2) Are Two Samples Significantly Different?---T Test 111(14) Independent T Test vs. Paired T Test 112(2) The Logic of the T Test 114(2) The Procedure of the T Test 116(2) Examples of T Tests Using Software 118(4) Requirements for Using T Test 122(3) Are Three or More Samples Significantly Different?---Analysis of Variance 125(14) The Logic of ANOVA 126(3) The Procedure for ANOVA 129(2) Example of ANOVA Using Software 131(2) Examining the Pattern of Difference 133(4) Requirements for Using ANOVA 137(2) When Data Do Not Behave---Using Nonparametric Tests 139(18) Spearman Correlation Coefficient 140(3) The Mann-Whitney Test 143(3) The Wilcoxon Signed Ranks Test 146(3) Kruskal-Wallis Test 149(4) Advantages and Disadvantages of Nonparametric Tests 153(4) Advantages of Nonparanmetric Tests 153(1) Disadvantages of Nonparametric Tests 153(1) When to Use a Nonparametric Test 154(3) When Should I Use Which Test?---A Road Map 157(6) Getting Sophisticated---A Taste of Some Advanced Statistical Methods 163(20) Two-Way ANOVA 163(8) Multiple-Regression 171(5) Why Do We Need Multiple Regression? 171(1) Multiple Regression Equation 172(1) Regression Coefficients 173(1) Multiple Correlation Coefficient and Multiple Coefficient of Determination 174(1) Partial Correlation Coefficient 175(1) LISREL 176(7) Appendices 183(16) Appendix 1 Standard Normal Distribution 185(2) Appendix 2 Random Number Table 187(2) Appendix 3 Critical Values of Chi-Square 189(2) Appendix 4 Critical Values of Pearson 1 191(2) Appendix 5 Critical Values of t 193(2) Appendix 6 Critical Values of F for ANOVA (α = 0.05) 195(2) Appendix 7 Critical Values for Tukey's HSD (α = 0.05) 197(2) Bibliography 199(2) About the Author 201(2) Index 203