Hi there. In this educational math/stats post I go over the stem and leaf plot. This plot seems to be popular in a lot of grade school data management curricula in the local schools (in the Toronto area).

<center><img src="https://cdn.pixabay.com/photo/2017/05/14/03/45/gui-2311261_960_720.png" /></center>
<center><a href="https://cdn.pixabay.com/photo/2017/05/14/03/45/gui-2311261_960_720.png">Pixabay Image Source</a></center>


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## Stem & Leaf Plots - A Way To Display Values
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Given a list of numbers, the stem and leaf plot is a way of organizing numbers based on the last (ones) digit called the leaf. The stem of a number is all the digits from the left to the second digit from the right. As an example the number 17 has a leaf of 7 and a stem of 1. The number 118 has a leaf of 8 and a stem of 11. 

The picture below is an example of a stem and leaf plot

<center><img src="https://www.softschools.com/math/topics/images/stem_leaf_plant_img_3.jpg" /></center>
<center><a href="https://www.softschools.com/math/topics/images/stem_leaf_plant_img_3.jpg">Duckduckgo Search Image</a></center>



The stem 6 contains the numbers 3 and 6 under the leaf section. This corresponds to the numbers 63 and 66. The key at the bottom provides additional context where the number represents an age.

Multiples of numbers are all listed. In the stem of 0 the ones are listed twice to represent two different people with the same age.

<center><img src="https://cdn.pixabay.com/photo/2018/08/18/13/27/browser-3614768_960_720.png" /></center>
<center><a href="https://cdn.pixabay.com/photo/2018/08/18/13/27/browser-3614768_960_720.png">Pixabay Image Source</a></center>

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## Examples
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**Example One**

We start with a simple stem and leaf plot example of student ages. 

Here is the list of student ages from elementary school, middle school and high school.

<center>`7, 13, 17, 9, 12, 11, 6, 12, 13, 8, 16, 15, 9, 10, 14, 11`</center>

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The stems for the ages are 0 (for zero tens) and 1. An optional step is to list out numbers that correspond to the stem of 0 and another list for the numbers with a stem of 1.

Stem 0 numbers: 7, 9, 6, 8, 9

Stem 1 numbers: 13, 17, 12, 11, 12, 13, 16, 15, 10, 14, 11

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When inserting numbers in the stem and leaf plot, make sure that the numbers in each of the stem rows are from smallest to largest.

| Stem  | Leaf  |
|---|---|
| 0  | 6, 7, 8, 9, 9  |
| 1  | 10, 11, 11, 12, 12, 13, 13, 14, 15, 16, 17  |

Key: 0 | 7 = 7 years old

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Since the stem and leaf plot sorts the ages in an organized manner, you can pick out the age of the youngest student and the age of the oldest student. 

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**Example Two**

This second example looks at people's weights in pounds. Here is the list of weights.

<center>`125, 131, 189, 201, 222, 145, 133, 170, 165, 191, 167, 210, 198`</center>

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The spread of values (range) is quite big here. It is best to go right into the stem and leaf plot.

| Stem  | Leaf  |
|---|---|
| 12  |  5 |
| 13  |  1, 3 |
| 14  |  5 |
| 15  |   |
| 16  | 5, 7 |
| 17  | 0  |
| 18  |  9 |
| 19  | 1, 8  |
| 20  | 1  |
| 21  | 0  |
| 22  | 2  |

Key: 19 | 2 = 192 lbs

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There is no value from 150 to 159 (inclusive) so the leaf part for the stem of 15 is blank.

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<center><img src="https://cdn.pixabay.com/photo/2018/07/15/11/27/online-3539412_960_720.png" /></center>
<center><a href="https://cdn.pixabay.com/photo/2018/07/15/11/27/online-3539412_960_720.png">Pixabay Image Source</a></center>

<center>Thank you for reading.</center>

Posted with [STEMGeeks](https://stemgeeks.net)