Bar Charts

A bar chart uses vertical bars to compare quantities, which are measured using a vertical axis.

For example, the chart below compares computer repair calls from three office buildings over periods of three months. Every bar graph has a “ruler” or scale on the left or right-hand side (usually the left). Typically the questions involve identifying values from within the chart and manipulating them.

Practice

1. Approximately how many more repair calls were made to 230 Park Place in 2009 than at 1215 Main Street?

2. By approximately how much did repairs increase at 16 General Pershing Street increase from the first quarter to the second quarter?

Comments

Answers to Practice Questions

1. About 55

230 Park Place has just over 20 repair calls in the first quarter and between 15 and 20 in the second and third quarters, and just under 15 in the fourth quarter. This yields a total of 70. 1215 Main Street has about 5 in both of the first two quarters and just under 5 for the last two, giving it a total of about 15.

2. About 5

In the first quarter, the repairs at 16 General Pershing are just over 10, while in the second quarter, they are between 15 and 20. This is an increase of about 5.