Step by step
The question
Question: make a stem-and-leaf plot of 15, 28, 33, 21, 47, 19, 26, 35, 42, 24, 31, 17, 29 and 38.
Find the median.
1 Split the numbers
The tens digit is the stem.
The ones digit is the leaf.
15: stem 1, leaf 5.
Careful!
Every plot needs a key.
1, line, 5 means 15, not 6.
2 Write the leaves
The stems go down the side: 1, 2, 3 and 4.
15: leaf 5 goes after stem 1.
We cross out 15.
28: leaf 8 after stem 2.
And so on, in the order they come.
3 Put the leaves in order
Now we write the plot again, with each row of leaves in order, smallest first.
Stem 1: 5, 7 and 9.
And the key: 1, line, 5 means 15.
4 Read the plot
The leaves are in order now.
We cross out the smallest and the biggest.
And the next pair, and so on.
Two are left in the middle: 28 and 29.
The median is halfway between them.
Halfway: we add them and divide by 2.
28 plus 29 is 57.
Divided by 2 is 28.5.
So the median is 28.5.
5 Check
Let's check: the plot has 14 leaves, one for each of the 14 numbers.
So none is lost!
Let's look back.
First: split the numbers.
Then: write the leaves.
Then: put the leaves in order.
Then: read the plot.
Last: check.