3) The weights (in kg) of 35 persons are given below: 43, 51, 47, 62, 48, 40, 50, 62, 53, 56, 40, 48, 56, 53, 50, 42, 55, 52, 48, 46, 45, 54, 52, 50, 47, 44, 54, 55, 60, 63,
58, 55, 60, 58, 53

a) Group this data by using the Sturges’ formula to determine the number of classes. Keep the width of
each class equal.
b) Find the mean, median, standard deviation and variance of the grouped data obtained in (a) above.

An office supply company conducted a survey before marketing a new paper shredder designed for home use. in the survey, 80 % of the people who tried the shredder were satisfied with it. because of this high satisfaction rate, the company decided to market the new shredder. assume that 80 % of all people are satisfied with this shredder. during a certain month, 100 customers bought this shredder. find the probability that of these 100 customers, the number who are satisfied is 69 or fewer.