CHAPTER 6

One-Variable Data Analysis

IN THIS CHAPTER

Summary: We begin our study of statistics by considering distributions of data collected on a single
variable. This will have both graphical and analytical components and is often referred to as exploratory
data analysis (EDA). “Seeing” the data can often help us understand it and, to that end, we will look at a
variety of graphs that display the data. Following that, we will consider a range of numerical measures
for center and spread that help describe the dataset. When we are finished, we will be able to describe a
dataset in terms of its shape , its center , and its spread (variability). We will consider both ways to
describe the whole dataset and ways to describe individual terms within the dataset. A very important
one-variable distribution, the normal distribution, will be considered in some detail.

Key Ideas

Shape   of  a   Distribution

Dotplot

Stemplot

Histogram

Measures    of  Center

Measures    of  Spread

Five-Number Summary

Boxplot

z   -Score

Density Curve

Normal  Distribution

The 68-95-99.7  Rule