Do "props" make a difference when researchers interact with their subjects? Emily and Madi asked 100 people if they thought buying coffee at Starbucks was a waste of money . Half of the subjects were asked while Emily and Madi were holding cups from Starbucks, and the other half of the subjects were asked when the girls were empty handed. The choice of holding or not holding the cups was determined at random for each subject. When holding the cups, 19 of 50 subjects agreed that buying coffee at Starbucks was a waste of money. When they weren't holding the cups, 23 of 50 subjects said it was a waste of money. Calculate and interpret a 90% confidence interval for the difference in the proportion of people like the ones in this experiment who would say that buying coffee from Starbucks is a waste of money when asked by interviewers holding or not holding a cup from Starbucks