Transcript Section 3.5 - Stem-and

Section 3.5 - Stem-and-Leaf
Plots
• We have been talking about different ways
to organize a set of data. We have used
tables, graphs, line plots, etc. Another way
we can use which uses the idea of a table
and some visual elements is the Stem-andLeaf Plot.
Stem-and-Leaf Plots
• So just as plants can be divided into two
parts: stem and leaves, we can also split a
set of numbers into their stems and leaves.
• Just as we found the range and scale of each
set of data to do plots, we will do the same
for making Stem-and-Leaf Plots.
How to Make a Stem-and-Leaf
Plot
1. Find the least and greatest values in the set
of data. This will give us a scale.
Ex. 3,24,16,98,13,33,77
The least value is 3. The greatest value is 98.
Our scale for this data is 3 through 98.
How to Make a Stem-and-Leaf
Plot
Stem- will be all of the digits of the number except
for the last digit (the digit all the way to the
right). The stem of each digit should have the
same decimal value.
2. Now we will determine the Stem for each
number in the set. We will make a table of the
stem and leaf of each value. So in the first
column of our table, we will put each stem
ranging from our smallest stem to our largest
stem.
How to Make a Stem-and-Leaf
Plot
• Step 2. Example Set 3,24,16,98,13,33,77
• So the Stems would be 0,2,1,9,1,3,7.
Notice that I include 0 because each stem
must have the same decimal value and each
number must have a stem. The decimal
value of each stem in this case would be
10’s. Why?
Range and Interval for the stems
• So what is the scale of the stems? 0-9
• What would be an interval we could use for
the stems? Let’s use 1’s. So When I make a
table of the stems, I put the stem values in
order from smallest to largest. The first
column would be
• 0,1,2,3,4,5,6,7,8,9
Table For Stem-and-Leaf
Stem (tens)
0
1
2
3
4
5
6
7
8
9
Leaves
In our first column of the Stemand-Leaf Plot, we will put our
stems. Use the scale and interval
to fill in this column.
Leaves
Leaf- the last digit of any number in the set (the digit
all the way to the right).
3. In the next column of our table, we will put our
leaves. Next to each stem, we will put every leaf
that has that same stem.
For example, 13 and 16 both have the same stem. So
next to the stem of 1 in our table, we will place
both a 3 and a 6.
Completing the table - Leaves
Stem (tens)
0
1
2
3
4
5
6
7
8
9
Leaves
3
36
4
3
In our leaves column, we place
every leaf that has the same stem.
In this table, what are the units of
the leaves?
Ones
7
8
A Key for our Data
•
So now we have found our Stems, Leaves, and
the decimal values of the Stems and Leaves.
4. Our final step is to make a Key for our table.
Key – A method for showing the viewer of your
stem-and-leaf plot the values of the stem and the
leaf.
Ex. For the stem-and-leaf plot we have just finished,
I can use the key 3 | 3 = 33. This Shows us that
the stems are in 10’s and the leaves are in 1’s.
Final Answer
Stem (tens)
0
1
2
3
4
5
6
7
8
9
Leaves (ones)
3
36
4
3
7
8
Key
3 | 3 = 33
I have stems, leaves, units for
the stem, units for the leaf, and a
key.
Practice Problems
•
Create a Stem-and-Leaf Plot for each of the
following data sets. Start by first writing the
numbers in order from smallest to largest.
1. 498,472,459,443,491,481,469,403,439,
444,411,492
2. 9.3,8.2,9.9,10,8,9.2,8.7,8,8.2,9,9.9,8.7,8.5,
8.1,8.8,9.3