A consumer group conducted a study regarding the number of hours of TV that teenagers watched per week. The cumulative frequencies of the sample were as follows.
Hours per week Cumulative Frequency
0-4 ................ 7
5-9 ............... 25
10-14 .............. 49
15-19 .............. 77
20-24 ............. 120
What is the mean "weekly hours of TV watched" for the sample?
a.) .38
b.) 12
c.) 15.42
d.) 17
e.) 370