Adam is practicing his selling on his grandfather, a salesmen himself since 1952. after the presentation, adam's grandfather tells him it was good, but he wasn't quite persuasive enough. what era of sales did his grandfather learn in?

The sales era

Explanation: The sales era occured in the 1920s and ran until the beginning of the 1950s. During this era, producers put increased pressure on making efffective sales, so they could identify customers who were interested in their product. Manufacturers would then use this info to produce just enough products that would correspond to their potential customers.

Firms were also nervous that if they did not stay relevant, then customers would forget to buy their products. So another tactic manufacturers would use to drive up sales was to release adverts often, that pursuaded customers to buy products that they didn't necessarily need.

answer; the coefficient of determination;