Drawing stem-and-leaf graphs activity

A stem-and-leaf graph is used to organise data as it is collected.

Tips on how to draw a stem-and-leaf graph

• A good stem-and-leaf graph shows the first digits of the number (tens, hundreds or thousands) as the stem and the last digit (units or ones) as a leaf.
• A good stem-and-leaf graph shows whole numbers, for example, class test results, house numbers, weight or height (rounded to whole numbers) or pulse rates.
• A good stem-and-leaf graph looks like a bar graph when its turned on its side.
• A good stem-and-leaf graph shows how the data is spread for example, the highest number, lowest number, most common number and outliers (a number that lies outside the main group of numbers).
• A good stem-and-leaf graph is followed by a short sentence telling what the stem-and-leaf graph shows. The stem-and-leaf graph can also be used to draw a graph.

Basic facts scores out of 20.

From the stem-and-leaf graph we can see that the highest basic facts score was 20 and the lowest score was 3. Most students scored between 10 and 20.

Activity

1. Show your class spelling scores or basic facts scores on a stem-and-leaf graph.
2. Tip the stem and leaf graph on its side so it looks like a bar graph. Are most of the scores under 10, between 10 and 19 or 20?
3. What was the most common score?
4. Collect your own basic fact scores for a term on a stem and leaf graph. What was your highest score? What was your most common score?

Related links

Statistics New Zealand Graphics Guidelines - 2. The process of graphing
Statistics New Zealand Graphics Guidelines - 4. Graphic Standards