The following are the duration in minutes of a sample of long-distance phone calls.
Relative
Time (in Minutes) Frequency
0 but less than 2 0.30
2 but less than 4 0.20
4 but less than 6 0.25
6 but less than 8 0.10
8 but less than 10 0.07
10 but less than 12 0.05
12 or more 0.03
If 80 calls were sampled, ________ of them would have lasted less than 15 minutes.
62
75
80
46
The total percentage frequency of calls less than 15 minutes is 0.30 + 0.20 + 0.25 + 0.10 + 0.07 + 0.05 = 0.97
0.97 * 80 = 77.6
Since you cannot have a fraction of a phone call, the number of calls that would have lasted less than 15 minutes is 77.