A stem-and-leaf plot, or stemplot, is used for organising and displaying numerical data. It is appropriate for small to moderately sized data sets.
In a stem-and-leaf plot, the right-most digit in each data value is split from the other digits, to become the 'leaf'. The remaining digits become the 'stem'.
All of the values in a stem-and-leaf plot are arranged in ascending order (from lowest to highest). For this reason, it is often called an ordered stem-and-leaf plot.
The data values $10,13,16,21,26,27,28,35,35,36,41,41,45,46,49,50,53,56,58$10,13,16,21,26,27,28,35,35,36,41,41,45,46,49,50,53,56,58 are displayed in the stem-and-leaf plot below.
Two sets of data can be displayed side-by-side using a back-to-back stem-and-leaf plot.
In the example below, the pulse rates of $18$18 students were recorded before and after exercise.
Reading a back-to-back stem-and-leaf plot is very similar to reading a regular stem-and-leaf plot.
Referring to the example above:
To create a stem-and-leaf plot, it is usually easier to arrange all of the data values in ascending order, before ordering them in the plot.
The data below shows the results of a survey conducted on the price of concert tickets locally and the price of the same concerts at an international venue.
Local | International | ||||||||||||||||||||||||||||||
|
|
Key: $1$1$\mid$∣$2$2$=$=$12$12 |
What was the most expensive ticket price at the international venue?
$\editable{}$ dollars
At the international venue, what percentage of tickets cost between $\$90$$90 and $\$110$$110 (inclusive)?
At the local venue, what percentage of tickets cost between $\$90$$90 and $\$100$$100 (inclusive)?
The stem-and-leaf plot shows the number of pieces of paper used over several days by Maximilian’s and Charlie’s students.
Maximilian | Stem | Charlie |
---|---|---|
$7$7 | $0$0 | $7$7 |
$3$3 | $1$1 | $1$1 $2$2 $3$3 |
$8$8 | $2$2 | $8$8 |
$4$4 $3$3 | $3$3 | $2$2 $3$3 $4$4 |
$7$7 $6$6 $5$5 | $4$4 | $9$9 |
$3$3 $2$2 | $5$5 | $2$2 |
Key: | $6\mid1\mid2$6∣1∣2 | $=$= | $16$16 and $12$12 |
Which of the following statements are true?
I. Maximilian's students did not use $7$7 pieces of paper on any day.
II. Charlie's median is higher than Maximilian’s median.
III. The median is greater than the mean in both groups.
I and II
II and III
None of the statements are correct.
III only
II only
I only