Step by step
The question
Question: make a stem-and-leaf plot of 91, 84, 78, 95, 88, 82, 99 and 86.
Find the median.
1 Split the numbers
The tens digit is the stem.
The ones digit is the leaf.
91: stem 9, leaf 1.
Careful!
Every plot needs a key.
9, line, 1 means 91, not 10.
2 Write the leaves
The stems go down the side: 7, 8 and 9.
91: leaf 1 goes after stem 9.
We cross out 91.
84: leaf 4 after stem 8.
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: 8.
And the key: 9, line, 1 means 91.
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: 86 and 88.
The median is halfway between them.
Halfway: we add them and divide by 2.
86 plus 88 is 174.
Divided by 2 is 87.
So the median is 87.
5 Check
Let's check: the plot has 8 leaves, one for each of the 8 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.