In a California gourmet market, researchers set up a booth of samples of Wilkin & Sons Jams. Every few hours, they switched from offering a selection of $24$ jams to a group of six jams. On average, customers tasted two jams, regardless of the size of the assortment, and each one received a coupon good for $$1$ off one Wilkin & Sons jam.

Interestingly, $60$ percent of customers were drawn to the large assortment, while only $40$ percent stopped by the small one. But $30$ percent of the people who had sampled from the small assortment decided to buy jam, while only $3$ percent of those confronted with the two dozen jams purchased a jar. Why such a large disparity in sales?