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Question

The number of phone calls arriving at a switchboard each hour has been recorded, and the following frequency distribution has been developed.
Class Interval Frequency
20-under 40 30
40-under 60 45
60-under 80 80
80-under 100 45

What is the midpoint of the last class?
a) 80
b) 100
c) 95
d) 90
e) 85

Answer

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