Frequency table and histogram
Paste your raw data and the frequency table and chart are prepared for you. Which chart to use when is explained in Chapter 2.
Sample data:
20 numbers read.
9 distinct values; with this few values, listing each one (simple table) is enough.
| Value | f | cf | rf | crf |
|---|---|---|---|---|
| 1 | 2 | 2 | 0.1 | 0.1 |
| 2 | 2 | 4 | 0.1 | 0.2 |
| 3 | 2 | 6 | 0.1 | 0.3 |
| 4 | 2 | 8 | 0.1 | 0.4 |
| 5 | 3 | 11 | 0.15 | 0.55 |
| 6 | 3 | 14 | 0.15 | 0.7 |
| 7 | 2 | 16 | 0.1 | 0.8 |
| 8 | 2 | 18 | 0.1 | 0.9 |
| 9 | 2 | 20 | 0.1 | 1 |
| Total | 20 | 1 |
f: frequency, cf: cumulative frequency, rf: relative frequency, crf: cumulative relative frequency
Bar chart: values are discrete, so the bars have gaps between them.
How was the table built?
Count how many times each value occurs: the frequency (f).
Add the frequencies one after another to get the cumulative frequency (cf). The last row must equal n.
Divide each frequency by n to get the relative frequency (rf); relative frequencies add up to 1.