A national survey has revealed that 40% of non-manual workers travel to work by public transport while one half use their own transport. For all workers, 47.5% use public transport and one in every ten, use methods other than their own or public transport. A statistical worker in a large factory (which is known to have about three times as many manual workers as non-manual workers) has been asked to sample 200 employees for their views on factory-provided transport. He decides to take a quota sample at factory gate 'B' at 4:00pm one evening.

A.) How many manual workers will there be in the sample?

B.) How many workers who travel to work by public transport will be interviewed?

C.) Calculate the quota to be interviewed in each of the six sub-groups defined

D.) Point out the limitations of the sampling method used and suggest a better way of collecting the data.

A.) How many manual workers will there be in the sample?

B.) How many workers who travel to work by public transport will be interviewed?

C.) Calculate the quota to be interviewed in each of the six sub-groups defined

D.) Point out the limitations of the sampling method used and suggest a better way of collecting the data.