Statistics For Dummies®, 2nd Edition

Chapter 5

Means, Medians, and More

In This Chapter

• Summarizing data effectively
• Interpreting commonly used statistics
• Realizing what statistics do and don't say

Every data set has a story, and if statistics are used properly, they do a good job of uncovering and reporting that story. Statistics that are improperly used can tell a different story, or only part of it, so knowing how to make good decisions about the information you're given is very important.

A descriptive statistic (or statistic for short) is a number that summarizes or describes some characteristic about a set of data. In this chapter, you see some of the most common descriptive statistics and how they are used, and you find out how to calculate them, interpret them, and put them together to get a good picture of a data set. You also find out what these statistics say and what they don't say about the data.

Summing Up Data with Descriptive Statistics

Descriptive statistics take a data set and boil it down to a set of basic information. Summarized data are often used to provide people with information that is easy to understand and that helps answer their questions. Picture your boss coming to you and asking, “What's our client base like these days, and who's buying our products?” How would you like to answer that question — with a long, detailed, and complicated stream of numbers that are sure to glaze her eyes over? Probably not. You want clean, clear, and concise statistics that sum up the client base for ...