Mean life of following distribution in the following distribution is 57.6 hours. If sum of frequency is 50 then find the missing frequency x and y
0−20 | 7 |
20−40 | x |
40−60 | 12 |
60−80 | y |
80−100 | 8 |
100−120 | 5 |
C.I | Frequency fi | Mid−value xi | fixi |
0−20 | 7 | 10 | 70 |
20−40 | x | 30 | 30x |
40−60 | 12 | 50 | 600 |
60−80 | y | 70 | 70y |
80−100 | 8 | 90 | 720 |
100−120 | 5 | 110 | 550 |
∑fi=32+x+y | ∑fixi=1940+30x+70y |