(b) The median and the mode of the following distribution are known to be 27 and 26

respectively.

Class 0-10 10-20 20-30 30-40 40-50

Frequency 3 a 20 12 b

(i) Show that the values of a and b are 8 and 7 respectively. (5 Marks)

(ii) Compute the arithmetic mean and the standard deviation of the distribution.(5 Marks)