The organisers of a town's flower show left a card at every stall asking visitors to name the kind of plant they would like more of, and report that of the 700 cards filled in and dropped in the box, roses were named oftenest. They propose to give roses a third of next year's stalls. Which of the following is an assumption on which the organisers' proposal depends?

The organisers propose to lay out the whole show for next year's visitors on the strength of 700 cards that a self-chosen minority of this year's visitors put in a box. The step holds only if the card-fillers stand for the visitors, and there is every reason they might not: the enthusiast who already grows roses will stop and write, while the family walking through will not. Deny the assumption and the 700 record the taste of a hobbyist fringe. The ground on which the show is held and the number of visitors expected bear on where and how large the show will be, not on what should fill it. What a rose costs a grower to bring bears on the cost of the plan, and a plan may be cheap and still be built on the wrong 700 people.