Practice 1
Back to back Stem & Leaf Plot
1 Draw a stem-and-leaf plot for each of the following sets of data. Be sure to create a
key for each.
a 101 113 117 104 112 123 102
117 118 111 100 120 127 112
b 8.4 7.6 5.2 8.1 9.0 8.8 7.2 5.1
c 19.5 19.4 18.2 20.3 21.5 17.1 18.0 20.6 20.5
d 1113 1120 1117 1119 1128 1126 1135 1111 1126 1125
2 The World Health Organization (WHO) set its standard for the acceptable amount
of lead in water at no more than 10 parts per billion. Water quality data (in parts per
billion) were collected from several rivers in Asia and displayed in the following
stem-and-leaf plot.
0 89
02356
237889
0024899
1
2
1 1
3
4
5
6
5668
2 2 3 3 3 6 89
01557
Key: 2|1=21
a How many tests resulted in water quality that met the WHO guideline?
b China sets its acceptable level of lead at no more than 50 parts per billion.
How many tests resulted in water quality that would not meet this guideline?
c How many tests contained lead levels between the United States' acceptable level
of 15 parts per billion and China's acceptable level?
d Are the lead levels represented in the table worrying? Explain.
3 Represent each of the following sets of data on a back-to-back stem and leaf plot.