(a) Describe 4 different types of sampling techniques.

(b) In an office, the weights of 21 people were taken and the following were observed in terms of kg:

91 72 79 86 95 78 69

77 123 99 64 101 86 75

106 84 68 98 82 73 83

(i) Form a grouped frequency distribution for the above data with the number of classes and class width being 5 and 12 respectively.

(ii) Using graph paper, draw a histogram to represent the frequency distribution for the grouped frequency data obtained above and estimate the mode.

(iii) Using the distribution obtained in (ii), evaluate an estimate of the mean and coefficient of variation.

(iv) Using graph paper, draw a box and whisker diagram to represent these data and comment on the shape of the distribution.