Biostatistics for the Clinician## Biostatistics for the Clinician

## University of Texas-Houston

Health Science Center## Lesson 1.7

## Distributions

Lesson 1: Summary Measures of Data 1/7 - 1

Biostatistics for the Clinician## 1.7 Distributions

## 1.7.1 Why Important?

Why do you need to know about frequency distributions, typically referred to just as "distributions"? Again, the answer is that they occur repeatedly in the medical research literature. To understand the literature and to be able to critically evaluate reported research studies so you can apply their results, you need to know about the distributions.What is meant by a distribution? A frequency distribution is simply a table, chart or graph which pairs each different value obtained with the number or proportion of times it occurs. So, anytime you have a set of values, each value may be plotted against the number or proportion of times it occurs using a graph having the values on the horizontal axis and the counts or proportions on the vertical axis. Such a graph is a very convenient way to represent a frequency distribution (see any of the figures below).

It turns out that some distributions are particularly important because they occur frequently in clinical situations. Some of the most important distributions are the Gaussian, the binomial and the Poisson distributions.