Stem-and-Leaf Plots

Chapter 6

Algebra 1

Ms. Mayer

Stem-and-Leaf Plot

Uses place value to organize data

Shows data in an organized way so it can be analyzed easily

Organizes data so it is easier to find the median, mode, and range

Stem-and-Leaf Plots: A convenient method to display every piece of data by showing the digits of each number.

How to Draw One:

1. Put the first digits of each piece of data in numerical order down the left-hand side

2. Go through each piece of data in turn and put the remaining digits in the proper row

3. Re-draw the diagram putting the pieces of data in the right order

4. Add a key

Stem-and-Leaf Plot

Here are the scores for a

freshman basketball team

Here is the same data organized into a stem-and-leaf plot.

Can you tell how the stem-and-leaf plot was made?

The first number in the data is 27.

Here is the 2 in the tens place.

Here is the 7 in the ones place.

The key shows us which place value the digits represent.

The stems all represent tens place in this stem-and-leaf plot. The leaves all

represent ones.

Let’s try one together…

Here are one student’s math test scores. Make a stem-and-leaf plot for this data.

First, draw the dividing lines.

Here are one student’s math test scores. Make a stem-and-leaf plot for this data.

Next, label the stem side and the leaf side. Stems Leaves

Here are one student’s math test scores. Make a stem-and-leaf plot for this data.

Find the smallest piece of data and plot it on the grid.

Stems Leaves 7 5

Here are one student’s math test scores. Make a stem-and-leaf plot for this data.

Find the next smallest piece of data and plot it on the grid.

Stems Leaves

7 5 9

The 7 for the tens place is already there. We just add the 9.

Continue with this process until you have entered all the data.

Stems Leaves 7 5 9

8 3 4 6 6 8

9 1 4 9

Remember to add a title.

Stems Leaves 7 5 9

8 3 4 6 6 8

9 1 4 9

Test Scores

Don’t forget the key!

Stems Leaves 7 5 9

8 3 4 6 6 8

9 1 4 9

Test Scores

Key: 7 5 means 75

You just completed a

stem-and-leaf plot!

Now, try it on your own…

This table shows the times in seconds and hundredths of seconds for the women’s 500-meter speed-skating competition in the 2002 Winter Olympics.

Use this data to make a stem-and-leaf plot.

2002 Winter Olympics 500-Meter Speed-Skating Times in Seconds

Check your work…

2002 Winter Olympics 500-Meter Speed-Skating Times in Seconds

Using Stem-and-Leaf Plots

What was the least number of cookies sold?

Boxes of Girl Scout Cookies Sold by Troop 220

40 boxes

Using Stem-and-Leaf Plots

What was the largest number of cookies sold?

Boxes of Girl Scout Cookies Sold by Troop 220

94 boxes

Using Stem-and-Leaf Plots

Find the median of the data

Find the middle leaf…

63 boxes

Boxes of Girl Scout Cookies Sold by Troop 220

Using Stem-and-Leaf Plots

Find the mode of the data Look for the number that occurs

most often in a row of leaves

63 boxes

Boxes of Girl Scout Cookies Sold by Troop 220

Remember:

- Always put in a Key

- Always put your data in Order

Median:

- to work out the median, you must find the middle value

- if there are two middle values, you need the average

Range:

- to work out the Range, subtract the smallest number from the biggest

Stem-and-Leaf Plots

Stem-and-Leaf Plots

The End!