Head First Statistics for Data Analysis

Chapter 3. Comparing Values First in Line

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Figure 3-1.  

Knowing where you stand can be really important.

You might want to know your position in a league table, or how many people are before you in a queue. In this chapter, we’ll focus on ways of describing a value’s position in a dataset. You’ll learn how to rank values, and use percentiles to find the top n%. You’ll use standard scores and standardization to make fair comparisons between values in different datasets. Along the way, you’ll meet the standard deviation, and find out why being normal can give you superpowers.

Statistics can describe a dataset’s values

In the previous chapter, you learned how to describe a dataset using statistics such as averages, skewness, quartiles, and ranges. These statistics help you determine the dataset’s middle value, how symmetrical the dataset ...