. PART 1 INTRODUCTION 3-27 1 Introduction: Purposes and Limitations of Statistics 3 2 Theory, Measurement, and Mathematics 11 . . PART 2 UNIVARIAE DESCRIPTIVE STATISTICS 30-104 3 Nominal Scales: Proportions, Percentages, and Ratios 31 4 Interval Scales: Frequency Distributions and Graphic Presentation 41 5 Interval Scales: Measures of Central Tendency 55 …