Download Chapter 10 - Data - Steam and leaf plot sheet 2

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MAT07SPWK10084_Stem_and_leaf_plots_2.3d] [2/2/012/12:49:55] [1–3]
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Worksheet
Stem-and-leaf plots 2
The heights of 28 students in a Year 7 class were measured (in cm). Here are the results:
182
166
166
172*
168*
161
175*
157
164
155
161*
173*
167
181
166*
168
165
165*
158*
163*
154
166
170*
181*
158
165
170*
170
(The 12 girls in the class are shown by *.)
These measurements can be grouped and listed in a stem-and-leaf plot.
Stem
Leaf
15
16
17
18
4
1
0
1
5
1
0
1
7
3
0
2
8
4
2
8
5
3
5
5
5
6
6
6
6
7
8
8
It groups the scores into ‘classes’; most heights are in the class ‘160–169’. An ordered stem-and-leaf plot is
useful for organising a large number of scores. It is more powerful than a column graph for statistical
calculations.
1 Use the stem-and-leaf plot to find:
a the modal height
b the median height
c the range
d the mean (correct to two decimal places)
e How many students had a height of over 171 cm?
2 Suppose we wish to compare the heights of boys and girls. We can do this using a back-to-back stemand-leaf plot. Complete the ordered plot below.
Girls
8
6
5
Boys
3
8 15 4
1 16 1
17
18
5
4
7
8
Note: Leaves branch outwards from the stem.
3 Just by looking at the distribution of scores, can you see which group:
a was taller, on average?
b had a greater spread of heights?
© Cengage Learning Australia Pty Ltd 2011
MAT07SPWK10084
Statistics and Probability: Data representation and interpretation
www.nelsonnet.com.au
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MAT07SPWK10084_Stem_and_leaf_plots_2.3d] [2/2/012/12:49:55] [1–3]
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4 Estimate (guess) the answers to complete the following table.
Girls
Boys
Median height
Mean height
5 Find the following measures (mean correct to one decimal place).
Girls
Boys
Modal height
Median height
Mean height
Range of heights
6 a How many boys were below 165 cm?
b How many girls were below 165 cm?
7 Write a brief report on what you have discovered about the differences between boys’ and girls’ heights in
the Year 7 class.
8 Measure the heights of the students in your class and display the data in a back-to-back stem-and-leaf
plot. Complete the table below and write a report on your conclusions.
Girls
Boys
Modal height
Median height
Mean height
Range of heights
© Cengage Learning Australia Pty Ltd 2011
MAT07SPWK10084
Statistics and Probability: Data representation and interpretation
www.nelsonnet.com.au
[Satish][NelsonNet Worksheet][D:/Thomson_Learning_Projects/NelsonNet_Worksheets_SB7_1080060/z_production/z_3B2_3D_files/Maths worksheet MS x 43/Student resources/NCM_Batch1/Worksheet/
MAT07SPWK10084_Stem_and_leaf_plots_2.3d] [2/2/012/12:49:55] [1–3]
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Answers
1 a 166 cm
b 166 cm
2
Boys
Girls
8
5
6
3
5
2
3
0
8
1
0
1
15
16
17
18
4
1
0
1
5
4
7
5
6
6
6
7
d 166.68 cm
8
2
b Boys
3 a Girls
5
8
5
c 28 cm
Girls
Boys
Mode
170
166
Median
169
165.5
Mean
168.5
165.3
Range
23
28
6 a 6
b 3
7 Girls taller on average; boys greater spread
8 Teacher to check
© Cengage Learning Australia Pty Ltd 2011
MAT07SPWK10084
Statistics and Probability: Data representation and interpretation
www.nelsonnet.com.au