The weekly pocket money (in rupees) received by a group of 40 students is recorded as follows.
(a) Pocket money (₹): 0–50 | 50–100 | 100–200 | 200–400 | 400–700
Frequency: 4 | 6 | 15 | 10 | 5
(b) (i) Express each class as a true class interval using suitable boundaries.
(c) (ii) Find the mean weekly pocket money of the students.
(d) (iii) Determine the population variance of the distribution.
(e) (iv) Comment briefly on what your answer to part (iii) indicates about the variability of pocket money among the students.