Objective
To make and interpret frequency tables and histograms
Essential Understanding There are many ways to organize and visually display data. Sometimes it is helpful to organize numerical data into intervals.
The frequency of an interval is the number of data values in that interval. A frequency table groups a set of data values into intervals and shows the frequency for each interval. Intervals in frequency tables do not overlap, do not have any gaps, and are usually of equal size.
Baseball The numbers of home runs by the batters in a local home run derby are listed below. What is a frequency table that represents the data?
7 17 14 2 7 9 5 12 3 10 4 12 7 15
The minimum data value is 2 and the maximum is 17. Intervals of 4 seem reasonable. In the first column of the table, list the intervals. Count the number of data values in each interval and list the number in the second column.
How do you choose intervals?
The data values range from 2 to 17, so there are a total of 16 possible values. You can divide these 16 values into 4 intervals of size 4.
Home Runs | Frequency |
---|---|
2–5 | 4 |
6–9 | 4 |
10–13 | 3 |
14–17 | 3 |