Pratik is a quality control officer for a biscuit company. He needs to check that 250 g of biscuits go into each packet, but realises that the weight in each packet will vary slightly.
(1) Would you expect the standard deviation for the whole population to be the same for one day as it is for one week? Explain your answer.
(2) If a sample of 100 packets is measured each day, what measure would be used to check:
- that an average of 250 g of biscuits goes into each packet
- the variability of the mass going into each packet?
(3) Explain the significance of a low standard deviation in this case.