Stem and Leaf Display in Biostatic

1. Stem and Leaf Display

2. Stem and Leaf display
A relatively small data set can be represent by stem and
leaf display. Each observation in stem and leaf display is
divided into two parts, a stem and a leaf.
 Stem is a leading digit of each number and is used
in sorting.
 Leaf is the rest of number or the trailing digit
and shown in display.
 A vertical line separates the leaf (or leaves) from stem.
Leading Digit Trailing Digit
Stem Leaf

3. Stem and Leaf display
Advantages
 More informative display for relatively small data set.
 The stem and leaf table provides a useful description of
data set and can easily be converted to a frequency
table.
 In addition to information on the number of
observations falling in the various classes, it
display details of what those observations actually
are.

4. Stem and Leaf display
Steps for stem and leaf display
 The choice of stem unit is important when constructing
stem and leaf display.
 Note the minimum and maximum value.
 Take a stem unit and also mention the width of class
also.
 Draw a vertical line and display the stem to the left of
the vertical bar.
 Attached the leaves to the right hand side of vertical
bar.

5. 5
Example
The following data is the final plant height (cm) of thirty
plants of wheat. Construct a frequency distribution
87 91 89 88 89 91 87
92 90 98 95 97 96 100
101 96 98 99 98 100 102
99 101 105 103 107 105 106
107 112

6. Stem and Leaf display
Example
Minimum value = 87 Maximum value = 112
Stem unit = 10 Width of class = 10
Stem Leaf
8
9
10
11
79897
1120857668989
01021537567
2

7. Stem and Leaf display
Arranged stem and leaf table
Stem Leaf
8
9
10
11
77899
0112566788899
00112355677
2

8. Stem and Leaf display
Example
Width of class = 5
Stem Leaf
8*
8.
9*
9.
10*
10.
11*
11.
-
79897
1120
857668989
010213
57567
2
-
* Indicates 0-4 . Indicates 5-9 [(*, .) are called place holder]

11. Back –to- Back Stem and Leaf display
Two data sets can be compared using Back-to-Back stem
and leaf display. In this case a single stem is constructed
and the values of one data set are assigned on the left and
the value of second data set are assigned on the right of
the stem.
Example: Compared using Back-to-Back stem and leaf
display
Data 1) 32 45 38 41 49 36 52
56 51 62 63 59 68
Data 2) 23 58 26 57 55 65 29
36 59 69 60

12. Back –to- Back Stem and Leaf display
Data 1 Data 2
32 = Mini. value = 23
68 = Maxi. value = 69
Stem unit = 10 Width of class = 10
Leaf Leaf
682
915
9162
832
2
3
4
5
6
369
6
8759
590
Data 1
(#13)
Data 2
(# 11)