Question 6 ---A marketing manager in a firm that makes washing-up liquid wants to find out if the lemon-scented and mint-scented versions are equally
liked by consumers. If they are not equally liked, then the firm may replace the less popular one by a new version.
Let p be the proportion of customers who prefer the lemon-scented to the mint-scented version. Out of 250 consumers who were interviewed, 145 said that they preferred the lemon-scented washing-up liquid, while the other 105 said that they preferred the mint-scented version.
(a) State appropriate null and alternative hypotheses.
(b) Carry out an appropriate hypothesis test at significance level 0.01. Report
(c) What sort of method of data collection was this? Give one concern that a
statistician might have about the way the data were collected.