Dive Into Data Science

3 Group Comparisons

In this chapter, we’ll discuss how to make intelligent comparisons between groups, using examples from business scenarios. We’ll start small by looking at one group alone. We’ll see which descriptive statistics most succinctly describe it, draw plots that capture its essence, and compare various samples from it. We’ll then be ready to reason about samples from two groups. We’ll conclude by looking at statistical significance tests: the t-test and the Mann-Whitney U test.

Reading Population Data

Let’s start by reading in some data. This data records measurements of 1,034 professional baseball players, including their height, ...