Chapter 3 Graphical and Numerical Summaries of Categorical Data. UNIT OBJECTIVES At the conclusion of this unit you should be able to: 1) Construct graphs that appropriately describe data 2) Calculate and interpret numerical summaries of a data set.
At the conclusion of this unit you should be able to:
“Sometimes you can see a lot just by looking.”
Hall of Fame Catcher, NY Yankees
For each individual who died in the United States in 2001, we record what was the cause of death. The table above is a summary of that information.
The number of individuals who died of an accident in 2001 is approximately 100,000.
Top 10 causes of death: bar graph
Each category is represented by one bar. The bar’s height shows the count (or sometimes the percentage) for that particular category.
Top 10 causes of deaths in the United States 2001
Top 10 causes of deaths in the United States 2001 approximately 100,000.
Bar graph sorted by rank
Easy to analyze
Much less useful
Top 10 causes of death: pie chart approximately 100,000.
Each slice represents a piece of one whole. The size of a slice depends on what
percent of the whole this category represents.
Percent of people dying from
top 10 causes of death in the United States in 2001
Make sure your approximately 100,000.
add up to 100.
Percent of deaths from top 10 causes
Percent of deaths from all causes
The poverty line is defined as 50% of national median income.
marg. dist. of survival intervention—UNICEF, 1996
marg. dist. of classContingency Tables: Categories for Two Variables
Given the class of a passenger, what is the chance the passenger survived?