Question :
| Daily expenditure (in Rupees) | 100 – 150 | 150 – 200 | 200 – 250 | 250 – 300 | 300 – 350 |
| Number of households | 4 | 5 | 12 | 2 | 2 |
Solution :
Let the assumed mean, A = 225, class size, h = 50
So, \(u_i\) = \(x_i – A\over h\) = \(x_i – 225\over 50\)
| Daily expenditure (in Rupees) | Mid – Values (\(x_i\)) | Frequency (\(x_i\)) | \(u_i\) = \(x_i – 225\over 50\) | \(f_iu_i\) |
| 100 – 150 | 125 | 4 | -2 | -8 |
| 150 – 200 | 175 | 5 | -1 | -5 |
| 200 – 250 | 175 | 12 | 0 | 0 |
| 250 – 300 | 225 | 2 | 1 | 2 |
| 300 – 350 | 325 | 2 | 2 | 4 |
| Total | 25 | -7 |
So, Mean = A + h\(\sum f_iu_i\over \sum f_i\) = 225 + 50 \(\times\) \(-7\over 25\) = 225 – 14 = 211
Hence, the mean daily expenditure on food is 211 rupees.
