Showing Orderly Data with Histograms

In bar graphs, the categories that data came from were related, but not numerical. In line graphs, the categories were related by a chronological and numerical order. A histogram is a special kind of bar graph where the categories are in numerical order and they are being grouped into intervals. For example, think about a survey that asks for the age of community college students. Instead of asking exact age, the survey groups the ages into intervals that are 10 years wide by having the respondent check a box for their age in one of the following intervals: 6 to 15, 16 to 25 or 26 to 35 or 36 to 45 or 46 to 55 or 56 to 65 or 66 to 75 or 76 to 85. Each interval is 10 years wide, and every person between the ages of 6 and 85 fits in an interval.