Statistic 7.5 The Median of a Frequency Distribution 7.6 The Mode 7.7 Relationship between Mean, Median and Mode
13 8 Measuring Variability 8.1 Variability 8.2 The Range 8.3 The Standard Deviation 8.4 Calculating the Standard Deviation 8.5 Calculating the Standard Deviation from Grouped Data 8.6 Variance 8.7 An Alternative Formula for Calculating the Variance and Standard Deviation 8.8 Degrees of Freedom 8.9 The Coefficient of Variation
14 9 Probability and the Normal Curve 9.1 The Meaning of Probability 9.2 Compound Probabilities 9.3 Critical Probability 9.4 Probability Distribution 9.5 The Normal Curve 9.6 Some Properties of the Normal Curve 9.7 Standardizing the Normal Curve 9.8 Two‐Tailed or One‐Tailed? 9.9 Small Samples: The t‐Distribution 9.10 Are our Data Normally Distributed? 9.11 Dealing with ‘Non‐normal’ Data
15 10 How Good Are our Estimates? 10.1 Sampling Error 10.2 The Distribution of a Sample Mean 10.3 The Confidence Interval of a Mean of a Large Sample 10.4 The Confidence Interval of a Mean of a Small Sample 10.5 The Difference between the Means of Two Large Samples 10.6 The Difference between the Means of Two Small Samples 10.7 Estimating a Proportion 10.8 The Finite Population Correction
16 11 The Basis of Statistical Testing 11.1 Introduction 11.2 The Experimental Hypothesis 11.3 The Statistical Hypothesis 11.4 Test Statistics 11.5 One‐Tailed and Two‐Tailed Tests 11.6 Hypothesis Testing and the Normal Curve 11.7 Type 1 and Type 2 Errors 11.8 Parametric and Non‐parametric Statistics: Some Further Observations 11.9 The Power of a Test
17 12 Analysing Frequencies 12.1 The Chi‐Square Test 12.2 Calculating the Test Statistic 12.3 A Practical Example of a Test for Homogeneous Frequencies 12.4 One Degree of Freedom – Yates' Correction 12.5 Goodness of Fit Tests 12.6 The Contingency Table – Tests for Association 12.7 The ‘Rows by Columns’ (r × c) Contingency Table 12.8 Larger Contingency Tables 12.9 Advice on Analysing Frequencies
18 13 Measuring Correlations 13.1 The Meaning of Correlation 13.2 Investigating Correlation 13.3 The Strength and Significance of a Correlation 13.4 The Product Moment Correlation Coefficient 13.5 The Coefficient of Determination r2 13.6 The Spearman Rank Correlation Coefficient rs 13.7 Advice on Measuring Correlations
19 14 Regression Analysis 14.1 Introduction 14.2 Gradients and Triangles 14.3 Dependent and Independent Variables 14.4 A Perfect Rectilinear Relationship 14.5 The Line of Least Squares 14.6 Simple Linear Regression 14.7 Fitting the Regression Line to the Scattergram 14.8 Regression for Estimation 14.9 The Coefficient of Determination in Regression 14.10 Dealing with Curved Relationships 14.11 How Can We ‘Straighten Up’ Curved Relationships?