Chapter 2: Displaying Data

Effective graphs are the principal means of

communicating results to a wider audience

Characteristics of a good graph

• Show the Data

• Make patterns in the data easy to see

• Represent magnitudes honestly

• Draw graphical elements clearly

Frequency table

It is used to display a frequency distribution for categorical or numerical data

One Variable Categorical Graph

Bar Graph

One Variable Numerical Graph

Histogram

Contingency Tables

describe the association between two (or more) categorical variables by displaying frequencies of all combinations of categories

Two Numerical Variable Graph

Scatter Plot

Two Categorical Variables

• Grouped bar graph

• Mosaic plot

One numerical variable and one categorical variable graph

• Strip Chart

• Violin Plot

• Multiple Histograms

• Cumulative frequency distribution

Outliers

Extreme data points lying well away from the rest of the data