Stem and leaf diagrams and box
plots
Statistics
Example 1
Draw a stem and leaf diagram using the set of data below.
148
135
119
147
93
107
145
87
113
103
111
110
113
110
104
Work out the quartiles and hence draw a box plot
Solution
8
7
9
3
10
3
4
7
11
0
0
1
7
8
Stem and leaf diagram
3
3
9
n = 15
13 | 5 represents 135
12
Min = 87
13
5
14
5
Q1 = 104
Q2 = 111
Boxplot
Q3 = 135
Max = 148
Example 2
Draw a stem and leaf diagram using the set of data below.
40
55
50
67
72
46
51
57
60
53
55
52
54
42
46
64
51
64
48
59
43
58
49
66
52
Work out the quartiles and hence draw a box plot
Stem and leaf diagram
Solution
n = 25
4 | 0 represents 40
Min = 40
4
0
2
3
6
6
8
9
5
0
1
1
2
2
3
4
6
0
4
4
6
7
7
2
Q1 = 48·5
Q2 = 53
Boxplot
Q3 = 59·5
5
5
7
Max = 72
8
9
Example 3
Draw a stem and leaf diagram using the set of data below.
157 166 145 154 159 136 143 145 142
154 152 160 147 177 135 158 141 155
155 157 150 152 145 147 152 159 142
Work out the quartiles and hence draw a box plot
Stem and leaf diagram
Solution
n = 27
13 | 5 represents 135
13 5 6
14 1 2 2 3 5 5 5 7 7
15 0 2 2 2 4 4 5 5 7 7 8 9 9
16 0 6
17 7
Min = 135
Q1 = 145
Q2 = 152
Boxplot
Q3 = 157
Max = 177
Example 4
Draw a stem and leaf diagram using the set of data below.
0.23 0.68 0.03 0.84 0.62 0.15 0.23 0.81
0.24 0.88 0.34 0.53 0.84 0.65 0.85 0.99
0.76 0.88 0.30 0.30 0.46 0.88 0.26 0.24
0.64 0.05 0.60 0.51 0.04 0.63 0.47 0.82
0.01 0.76 0.76 0.68 0.11 0.51 0.99 0.02
Work out the quartiles and hence draw a box plot
Solution
Stem and leaf diagram
n = 40
2 | 3 represents 0.23
Min = 0·01
Q1 = 0·235
Q2 = 0·52
Boxplot
0
1
2
3
4
5
1
1
5
2
3
3
4
4
6
3
0
0
4
4
6
7
5
1
1
3
6
0
2
3
4
5
8
8
7
6
6
6
8
1
2
4
4
5
8
8
9
9
9
Q3 = 0·815
Max = 0·99
8