Step by step
The question
Question: make a stem-and-leaf plot of 85, 92, 78, 88, 95, 81, 90, 76, 84, 89, 93 and 87.
Find the median.
1 Split the numbers
The tens digit is the stem.
The ones digit is the leaf.
85: stem 8, leaf 5.
Careful!
Every plot needs a key.
8, line, 5 means 85, not 13.
2 Write the leaves
The stems go down the side: 7, 8 and 9.
85: leaf 5 goes after stem 8.
We cross out 85.
92: leaf 2 after stem 9.
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 7: 6 and 8.
And the key: 8, line, 5 means 85.
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: 87 and 88.
The median is halfway between them.
Halfway: we add them and divide by 2.
87 plus 88 is 175.
Divided by 2 is 87.5.
So the median is 87.5.
5 Check
Let's check: the plot has 12 leaves, one for each of the 12 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.