Happy Alice Ptd. Ltd. has recorded the monthly sales made by 40 salesmen.The data are shown in the table below.

Monthly sales (RM) Number of salesmen

101 - 150 4

151 - 200 8

201 - 250 6

251 - 350 20

351 - 450 2

(a)State whether the values shown in the table are class limits or class boundaries.

(b)What is the middle point of the third class?

(c)Compute the sample

(i)mean

(ii) variance

(iii)standard deviation

(d)Illustrate the data by plotting an ogive.

(e)Estimate the median for the monthly sales graphically.