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
What is the cumulative relative frequency for the percentage of calls that lasted under 6 minutes?
0.45
0.60
0.75
0.84
To find the cumulative relative frequency for calls that lasted under 6 minutes, we need to add up the relative frequencies for calls that lasted under 6 minutes.
This includes the frequencies for 0-2 minutes, 2-4 minutes, and 4-6 minutes.
Relative frequency for 0-2 minutes = 0.30
Relative frequency for 2-4 minutes = 0.20
Relative frequency for 4-6 minutes = 0.25
Adding these together, we get 0.30 + 0.20 + 0.25 = 0.75
Therefore, the cumulative relative frequency for calls that lasted under 6 minutes is 0.75.
So, the correct answer is: 0.75