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Question
Find the mean deviation about the mean of the following data:
| Size (x): | 1 | 3 | 5 | 7 | 9 | 11 | 13 | 15 |
| Frequency (f): | 3 | 3 | 4 | 14 | 7 | 4 | 3 | 4 |
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Solution
Mean = `barx = (f_i x_i)/(f_i)`
= `(3 + 9 + 20 + 98 + 63 + 44 + 39 + 60)/42`
= `336/42`
= 8
M.D. `(barx) = (f_i |x_i - barx|)/(f_i)`
= `(3(7) + 3(5) + 4(3) + 14(1) + 7(1) + 4(3) + 3(5) + 4(7))/42`
= `(21 + 15 + 12 + 14 + 7 + 12 + 15 + 28)/42`
= `62/21`
= 2.95
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