Market researchers are testing customers’ preferences for five products. There are four researchers who are allocated to different groups: researcher R1 deals with men under 40, R2 deals with men over...

Market researchers are testing customers’ preferences for five products. There are four researchers who are allocated to different groups: researcher R1 deals with men under 40, R2 deals with men over 40, R3 deals with women under 40 and R4 deals with women over 40. They return their findings as a vector giving the number of customers with first preference for a particular product.