Step by step
The question
Question: make a stem-and-leaf plot of 12, 25, 18, 21, 14, 29 and 16.
Find the median.
1 Split the numbers
The tens digit is the stem.
The ones digit is the leaf.
12: stem 1, leaf 2.
Careful!
Every plot needs a key.
1, line, 2 means 12, not 3.
2 Write the leaves
The stems go down the side: 1 and 2.
12: leaf 2 goes after stem 1.
We cross out 12.
25: leaf 5 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: 2, 4, 6 and 8.
And the key: 1, line, 2 means 12.
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.
One leaf is left in the middle: it is 18.
So the median is 18.
5 Check
Let's check: the plot has 7 leaves, one for each of the 7 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.