Workshop Statistics: Discovery with Data, Fourth Edition

TOPIC 7

Displaying and Describing Distributions

How much do Olympic rowers typically weigh, and how much variability do these weights reveal? Why does one member of the rowing team weigh so much less than all of his teammates? Do famous poets tend to produce their greatest works at younger or older ages? Did eastern or western states tend to experience more population growth in the 2000s? These are some of the questions you will investigate in this topic that introduces you to analyzing quantitative data.

Overview

In the previous topic, you examined ways to summarize categorical data both graphically and numerically by creating two-way tables and segmented bar graphs and calculating conditional proportions and relative risk. In this topic and in the next several, you will turn your attention to summarizing quantitative data. Previously in Topic 2, you learned about using dotplots for displaying the distribution of relatively small datasets of a quantitative variable, and you began to comment on the center and spread of the distribution. In this topic, you will discover some more key features of a distribution and also become familiar with two new visual displays: stemplots and histograms.

Preliminaries

1. What do you think is a typical weight for a male Olympic rower? (Activity 7-2)
2. Take a guess as to the typical age of poets when they create their most famous poems. (Activity 7-3)
3. Do you think states in the eastern or western United States tended to have greater population growth ...