Biostatistics

Chapter 5

Dispersion

Objectives

After completing this chapter, you can understand the following:

• The definition, meaning and significance of dispersion.
• The calculation of different dispersions such as range, quartiles, quartile deviation, standard deviation [SD] and coefficient of variation [CV].
• Managerial applications using SD and CV.
• How these measures can be used to make decisions related to biological studies?

5.1 INTRODUCTION

An average gives a single value that is considered to be representative of the whole group, but it is not going to reveal how the items in the groups are scattered or spread.

Example:

Six boys having the marks 100, 100, 100, 0, 0 and 0; another group of six boys have the marks as 50, 60, 50, 50, 40 and 50. Both ...