Numerical data: more than two groups
The Problem We have samples from a number of independent groups. We have a single numerical or ordinal variable and are interested in whether the average value of the variable…
Bayesian methods
The Frequentist Approach The hypothesis tests described in this book are based on the frequentist approach to probability (Chapter 7) and inference that considers the number of times an event…
Cohort studies
A cohort study takes a group of individuals and usually follows them forward in time, the aim being to study whether exposure to a particular aetiological factor will affect the…
Regression methods for clustered data
Various regression methods can be used for the analysis of the two-level hierarchical structure described in Chapter 41, in which each cluster (level 2 unit) contains a number of individual…
Case–control studies
A case–control study compares the characteristics of a group of patients with a particular disease outcome (the cases) to a group of individuals without a disease outcome (the controls), to…
Numerical data: a single group
19 Numerical Data: a Single Group The Problem We have a sample from a single group of individuals and one numerical or ordinal variable of interest. We are interested in…
Categorical data: more than two categories
Chi-Squared Test: Large Contingency Tables The Problem Individuals can be classified by two factors. For example, one factor may represent disease severity (mild, moderate, severe) and the other factor may…
Categorical data: a single proportion
The Problem We have a single sample of n individuals; each individual either ‘possesses’ a characteristic of interest (e.g. is male, is pregnant, has died) or does not possess that…
Confidence intervals
Once we have taken a sample from our population, we obtain a point estimate (Chapter 10) of the parameter of interest, and calculate its standard error to indicate the precision…
Survival analysis
Survival data are concerned with the time it takes an individual to reach an endpoint of interest (often, but not always, death) and are characterized by the following two features….
