The analyst at SmartWool (see For Example: “Setting the a level for website customers”) makes another change to the website, puts it online, selects 200 recent web visits at random, and finds that 29% of them have resulted in a sale.
Would this be a surprising proportion of sales if the true proportion of sales were 20%? We are interested in whether the proportion of visits resulting in a sale has changed since the new website went live. Comment on the statistical and business significance of this result.