Bar Graphs Histograms Copyright 2002 N Ahbel Bar

Bar graphs can be used when one variable is categorical Copyright © 2002, N. Ahbel Source: US Census Bureau, Statistical Abstract of the U. S. , http: //www. census. gov/prod/2001 pubs/statab/sec 08. pdf, 7/29/03

In this case the categories are Democrat, Republican, and Other major candidates Copyright © 2002, N. Ahbel Source: US Census Bureau, Statistical Abstract of the U. S. , http: //www. census. gov/prod/2001 pubs/statab/sec 08. pdf, 7/29/03

Histograms can be used when one variable is numerical. (Not used for categorical data).

Values of the numerical variable are divided into equal width intervals or bins. Copyright © 2002, N. Ahbel In this case the interval width is 1% and this interval includes states that have non-coverage in the interval 9% ≤ x < 10%.

Histograms intervals include either the left endpoint or the right, but not both. This histogram includes the left endpoint. Copyright © 2002, N. Ahbel A state with exactly 9% non-coverage is counted in this interval.

Histograms intervals include either the left endpoint or the right, but not both. This histogram includes the left endpoint. Copyright © 2002, N. Ahbel A state with exactly 10% non-coverage is counted in this interval.

This is a Frequency Histogram. It gives the frequency or count of states in

This is a Relative Frequency Histogram. It gives the percent of states in each

Appropriate for? Shown on Display? Individual Data Values 5 -Number Summary Mean Frequency Histogram No No Relative Frequency Histogram No No Important Characteristics: Std. Dev. Large Data Sets Small Data Sets No No Yes OK Displays number of values in each interval No No Yes No Displays the percent in each interval Copyright © 2002, N. Ahbel