Tally charts
A tally chart is a simple way of recording and counting frequencies. Each occurrence is shown by a tally mark and every fifth tally is drawn diagonally to make a “gate” of five. The tallies can then be counted to give the frequency.
Example
20 pupils were asked about their favourite type of movie.
| Movie genre | Tally | Frequency |
| Horror | \({|||}\) | 3 |
| Action | \(\cancel{||||}~{||}\) | 7 |
| Romance | \({||||}\) | 4 |
| Comedy | \(\cancel{||||}\) | 5 |
| Other | \({|}\) | 1 |
| Movie genre | Horror |
|---|---|
| Tally | \({|||}\) |
| Frequency | 3 |
| Movie genre | Action |
|---|---|
| Tally | \(\cancel{||||}~{||}\) |
| Frequency | 7 |
| Movie genre | Romance |
|---|---|
| Tally | \({||||}\) |
| Frequency | 4 |
| Movie genre | Comedy |
|---|---|
| Tally | \(\cancel{||||}\) |
| Frequency | 5 |
| Movie genre | Other |
|---|---|
| Tally | \({|}\) |
| Frequency | 1 |
Pictograms
A pictogram shows the frequency of events using pictures. A key that shows what each picture is worth is needed to be able to read a pictogram properly.
Example
The favourite type of movie frequencies can be shown on a pictogram.
Bar charts
A bar chart shows the frequency using bars. The height of the bar represents the frequency.
Example
The favourite type of movie frequencies can be shown in a bar chart.
Comparative bar charts
Bar charts can be used to compare data.
The following frequency table summarises the number of pets owned by some children.
| No pets | 1 pet | 2 pets | 3 or more pets | |
| Boys | 2 | 4 | 2 | 3 |
| Girls | 3 | 3 | 2 | 1 |
| Boys | |
|---|---|
| No pets | 2 |
| 1 pet | 4 |
| 2 pets | 2 |
| 3 or more pets | 3 |
| Girls | |
|---|---|
| No pets | 3 |
| 1 pet | 3 |
| 2 pets | 2 |
| 3 or more pets | 1 |
A comparative bar chart can show this information. A key is needed to be able to read the bar chart properly.
For example, the chart shows that five children had no pets, and the coloured shading shows that two of the children were boys and three were girls.