1. Young adults by gender and chance of getting rich
Analyzing Categorical Data
Categorical data is data divided in categories and
each category has a corresponding value
Ways to display categorical data:
Bar Graph Circle Graph Two Way Table
Young adults by gender and chance of getting rich
Female
Male
Total
Almost no chance 96 98
194
Some chance, but probably not
426
286
712
A chance
696
720
1416
A good chance
663
758
1421
Almost certain
486
597
1083
2367
2459
4826

2. Why do the bars on the two graphs look so relatively different?
Graphs: Good and Bad
Bar graphs compare several quantities by comparing the heights of bars that represent those quantities. Our eyes, however, react to the area of the bars as well as to their height.
Why do the bars on the two graphs look so relatively different?
Looks 10 times taller than PC

3. Which graph is best?
Portable music players are popular, but not equally with people of all ages. Below is a chart of the percent of people within each group that own a portable music player (non-phone), according to a survey of 1112 randomly selected people.
Which type of categorical graph would be most appropriate for this data?

4. Two Way Tables
These allow for analysis of the distribution of a single categorical variable
Example: A survey of randomly selected young adults (19 – 25 years old) asked “What do you think the chances are that you will have MORE than a middle class income?” The table below gives their responses.
What percent of the people believed a chance?
What percent of the people were almost certain?
The totals are called MARGINAL DISTRIBUTIONS.

5. Conditional Distributions describe the value of a variable based upon the value of another variable.
What percentage of females claimed there is almost no chance?
What percent of those claiming a good chance are male?

6. Two Way Tables can be displayed in graphs as well.
Double Bar Graph
Stacked Bar Graph

7. Two Way Tables also allows us to determine if there is an association between two variables.
This means knowing the value of one variable will help you
predict the value of another.
Is there an association between gender and opinion about financial status?