The mean of the following frequency dristibution is 50. Find the value of p
Class | 0 - 20 | 20 - 40 | 40 - 60 | 60 - 80 | 80 - 100 |
Frequency | 17 | 28 | 32 | p | 19 |
class intervals | frequency (fi) | xi | di = xi - A | fi di |
0 - 20 | 17 | 10 | -40 | -680 |
20 - 40 | 28 | 30 | -20 | -560 |
40 - 60 | 32 | 50 = A | 0 | 0 |
60 - 80 | p | 70 | 20 | 20p |
80 - 100 | 19 | 90 | 40 | 760 |
total | Σ fi = 96 + p | Σ fi di = 20p - 480 |