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| Preface | |
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| Foreword to Students | |
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| Introduction | |
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| What do we mean by statistics? | |
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| Why is statistics necessary? | |
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| The limitations of statistics | |
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| Calculators and computers in statistics | |
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| The purpose of this text | |
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| Health Care Investigations: Measurement and Sampling Concepts | |
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| Introduction | |
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| Populations, samples and observations | |
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| Counting things--the sampling unit | |
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| Sampling strategy | |
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| Target and study populations | |
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| Sample designs | |
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| Simple random sampling | |
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| Systematic sampling | |
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| Stratified sampling | |
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| Quota sampling | |
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| Cluster sampling | |
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| Sampling designs--summary | |
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| Statistics and parameters | |
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| Descriptive and inferential statistics | |
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| Parametric and non-parametric statistics | |
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| Processing Data | |
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| Scales of measurement | |
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| The nominal scale | |
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| The ordinal scale | |
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| The interval scale | |
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| The ratio scale | |
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| Conversion of interval observations to an ordinal scale | |
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| Derived variables | |
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| Logarithms | |
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| The precision of observations | |
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| How precise should we be? | |
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| The frequency table | |
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| Aggregating frequency classes | |
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| Frequency distribution of count observations | |
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| Bivariate data | |
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| Presenting Data | |
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| Introduction | |
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| Dot plot or line plot | |
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| Bar graph | |
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| Histogram | |
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| Frequency polygon and frequency curve | |
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| Scattergram | |
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| Circle or pie graph | |
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| Clinical Trials | |
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| Introduction | |
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| The nature of clinical trials | |
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| Clinical trial designs | |
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| Psychological effects and blind trials | |
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| Historical controls | |
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| Ethical issues | |
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| Case study: Leicestershire Electroconvulsive Therapy (ECT) study | |
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| Summary | |
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| Introduction to Epidemiology | |
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| Introduction | |
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| Measuring disease | |
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| Study designs--cohort studies | |
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| Study designs--case-control studies | |
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| Cohort or case-control study? | |
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| Choice of comparison group | |
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| Confounding | |
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| Summary | |
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| Measuring the Average | |
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| What is an average? | |
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| The mean | |
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| Calculating the mean of grouped data | |
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| The median--a resistant statistic | |
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| The median of a frequency distribution | |
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| The mode | |
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| Relationship between mean, median and mode | |
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| Measuring Variability | |
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| Variability | |
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| The range | |
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| The standard deviation | |
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| Calculating the standard deviation | |
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| Calculating the standard deviation from grouped data | |
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| Variance | |
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| An alternative formula for calculating the variance and standard deviation | |
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| Obtaining the standard deviation and sum of squares from a calculator | |
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| Degrees of freedom | |
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| The Coefficient of Variation (CV) | |
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| Probability and the Normal Curve | |
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| The meaning of probability | |
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| Compound probabilities | |
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| Critical probability | |
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| Probability distribution | |
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| The normal curve | |
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| Some properties of the normal curve | |
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| Standardizing the normal curve | |
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| Two-tailed or one-tailed? | |
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| Small samples: the t-distribution | |
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| Are our data 'normal'? | |
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| Dealing with 'non-normal' data | |
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| How Good are Our Estimates? | |
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| Sampling error | |
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| The distribution of a sample mean | |
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| The confidence interval of a mean of a large sample | |
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| The confidence interval of a mean of a small sample | |
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| The difference between the means of two large samples | |
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| The difference between the means of two small samples | |
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| Estimating a proportion | |
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| The finite population correction | |
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| The Basis of Statistical Testing | |
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| Introduction | |
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| The experimental hypothesis | |
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| The statistical hypothesis | |
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| Test statistics | |
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| One-tailed and two-tailed tests | |
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| Hypothesis testing and the normal curve | |
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| Type 1 and type 2 errors | |
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| Parametric and non-parametric statistics: some further observations | |
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| The power of a test | |
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| Analysing Frequencies | |
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| The chi-squared test | |
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| Calculating the test statistic | |
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| A practical example of a test for homogeneous frequencies | |
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| One degree of freedom--Yates' correction | |
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| Goodness of fit tests | |
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| The contingency table--tests for association | |
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| The 'rows by columns' (r x c) contingency table | |
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| Larger contingency tables | |
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| Advice on analysing frequencies | |
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| Measuring Correlations | |
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| The meaning of correlation | |
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| Investigating correlation | |
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| The strength and significance of a correlation | |
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| The Product Moment Correlation Coefficient | |
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| The coefficient of determination r[superscript 2] | |
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| The Spearman Rank Correlation Coefficient r[subscript s] | |
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| Advice on measuring correlations | |
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| Regression Analysis | |
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| Introduction | |
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| Gradients and triangles | |
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| Dependent and independent variables | |
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| A perfect rectilinear relationship | |
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| The line of least squares | |
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| Simple linear regression | |
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| Fitting the regression line to the scattergram | |
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| Regression for estimation | |
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| The coefficient of determination in regression | |
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| Dealing with curved relationships | |
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| How we can 'straighten up' curved relationships? | |
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| Advice on using regression analysis | |
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| Comparing Averages | |
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| Introduction | |
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| Matched and unmatched observations | |
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| The Mann--Whitney U-test for unmatched samples | |
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| Advice on using the Mann--Whitney U-test | |
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| More than two samples--the Kruskal--Wallace test | |
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| Advice on using the Kruskal--Wallace test | |
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| The Wilcoxon test for matched pairs | |
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| Advice on using the Wilcoxon test for matched pairs | |
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| Comparing means--parametric tests | |
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| The z-test for comparing the means of two large samples | |
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| The t-test for comparing the means of two small samples | |
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| The t-test for matched pairs | |
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| Advice on comparing means | |
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| Analysis of Variance--Anova | |
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| Why do we need ANOVA? | |
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| How ANOVA works | |
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| Procedure for computing ANOVA | |
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| The Tukey test | |
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| Further applications of ANOVA | |
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| Advice on using ANOVA | |
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| Appendices | |
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| Table of random numbers | |
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| t-distribution | |
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| x[superscript 2]-distribution | |
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| Critical values of Spearman's Rank Correlation Coefficient | |
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| Critical values of the product moment correlation coefficient | |
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| Mann--Whitney U-test values (two-tailed test) | |
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| Critical values of T in the Wilcoxon test for matched pairs | |
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| F-distribution | |
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| Tukey test | |
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| Symbols | |
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| Leicestershire ECT study data | |
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| How large should our samples be? | |
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| Bibliography | |
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| Index | |