Transformations
Why Transform? The observations in our investigation may not comply with the requirements of the intended statistical analysis (Chapter 35). A variable may not be Normally distributed, a distributional requirement…
Developing prognostic scores
Why Do We Do It? Given a large number of demographic or clinical features of an individual, we may want to predict whether that individual is likely to experience an…
Presenting results
Introduction An essential facet of statistics is the ability to summarize the important features of the analysis. We must know what to include and how to display our results in…
Errors in hypothesis testing
Making a Decision Most hypothesis tests in medical statistics compare groups of people who are exposed to a variety of experiences. We may, for example, be interested in comparing the…
Explanatory variables in statistical models
Whichever type of statistical model we choose, we have to make decisions about which explanatory variables to include in the model and the most appropriate way in which they should…
Theoretical distributions: other distributions
Some Words of Comfort Do not worry if you find the theory underlying probability distributions complex. Our experience demonstrates that you want to know only when and how to use…
Evidence-based medicine
Straus et al. 1 describe evidence-based medicine (EBM) as ‘the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients’. To practice…
Hypothesis testing
We often gather sample data in order to assess how much evidence there is against a specific hypothesis about the population. When performing descriptive analyses (Chapters 4–6) we may see…
