Frequency distribution
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Frequency Distribution
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Examples
Pulse rates, in beats per minute, were calculated for [math]192[/math] students enrolled in a statistics course at the University of Adelaide.[1] The following table provides the count and percent for the data values grouped into class intervals.
| Pulse Rate | Count | Percent |
|---|---|---|
| (34-41] | 2 | 1.0% |
| (41-48] | 2 | 1.0% |
| (48-55] | 4 | 2.1% |
| (55-62] | 19 | 9.9% |
| (62-69] | 40 | 20.8% |
| (69-76] | 53 | 27.6% |
| (76-83] | 30 | 15.6% |
| (83-90] | 27 | 14.1% |
| (90-97] | 10 | 5.2% |
| (97-104] | 5 | 2.6% |
| Total | 192 | 100.0% |
Tip: It is very important that each observation be counted only in one interval. However, in the frequency table above, it seems like an observation that borders on two intervals is included in both, because the upper limit of each interval is also the lower limit of the next interval. To avoid double counting observations, the intervals are written to communicate when the limit is included and when it is not. The square bracket means "including" and the parenthesis means "not including". For example, [math](69-76][/math] is the interval from [math]69[/math] to [math]76[/math], not including [math]69[/math], but including [math]76[/math]. That is, data values are included in this range when [math]\ 69 \lt data\ value \le 76\,[/math].
