Calculate the mean of the following data, using direct method:
Class25−3535−4545−5555−6565−75Frequency6108124
Class | Frequency (fi) | Mid Values (xi) | (∑fixi) |
25 - 35 | 6 | 30 | 180 |
35 - 45 | 10 | 40 | 400 |
45 - 55 | 8 | 50 | 400 |
55 - 65 | 12 | 60 | 720 |
65 - 75 | 4 | 70 | 280 |
Total | ∑fi=40 | ∑fixi=1980 |
Therefore, Mean, ¯x=∑fixi∑fi
= 1980/40 = 49.5
Therefore, ¯x = 49.5