need to find the median from frequency table??

[car.man]

need to find the median:

Group Frequency
0-4 2
5-9 3
10-14 7
15-19 5
20-24 3

[testing]

There are 2+3+7+5+3=20 points, so the median is the average of the 10th & 11th. But you have classes, not the actual points, so you have to start at the bottom of the interval (10-14, probably 9.5). The 10th point is 5th (of 7) in the interval & the interval is 5 wide, so its 9.5+(5/7)(5).