Cumulative Frequency

1
Cumulative Frequency

• 27-May-14

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2

The following gives information from a survey of
47 students about the time taken by them to eat
their breakfast in the morning.
Time in minutes frequency
0 lt t 5 10
5 lt t 10 16
10 lt t 15 14
15 lt t 20 4
20 lt t 25 2
25 lt t 30 1

• Draw the cumulative frequency graph and use this
  to find
• The median
• The interquartile range

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3

The following gives information from a survey of
47 students about the time taken by them to eat
their breakfast in the morning.
Time in minutes frequency
0 lt t 5 10
5 lt t 10 16
10 lt t 15 14
15 lt t 20 4
20 lt t 25 2
25 lt t 30 1
Cumulative frequency
10
26
40
44
46
47

• Draw the cumulative frequency graph and use this
  to find
• The median
• The interquartile range

More resources available from free-online-calcula
tor.net
4
Time in minutes Cumulative frequency
0 lt t 5 10
5 lt t 10 26
10 lt t 15 40
15 lt t 20 44
20 lt t 25 46
25 lt t 30 47
60
50
40
Cumulative frequency
30
20
10
The upper boundary for each class interval is
plotted against its cumulative frequency.
30
40
10
20
Time in minutes
Middle value is ½ X (471) 24
The time associated with the 24th value gives us
a median of 9 minutes.
Upper Quartile 14 minutes. Lower Quartile 6
minutes.
The lower quartile is ¼ X (471)th vaue. The
upper quartile is 3/4 X (471)th vaue.
Interquartile range 14 6 8
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