Biostatistics For Dummies

Chapter 8

Summarizing and Graphing Your Data

In This Chapter

Representing categorical data

Characterizing numerical variables

Putting numerical summaries into tables

Displaying numerical variables with bars and graphs

A large study can involve thousands of subjects, hundreds of different variables, and millions of individual pieces of data. Even a small research project normally generates much more data than you can (or would want to) put into a publication or report. Instead, you need to boil the individual values for each variable down to a few numbers, called summary statistics, that give readers an idea of what the whole collection of numbers looks like — that is, how they’re distributed.

When presenting your results, you may want to arrange these summary statistics into tables that describe how the variables change over time or differ between treatments, or how two or more variables are related to each other. And, because a picture really is worth a thousand words, you probably want to display these distributions, changes, differences, and relationships graphically.

In this ...