AP Statistics Chapter 10 Review Question:
- 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.
50 of the subjects were asked while Emily and Madi
were holding cups from Starbucks, and the other
50 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. Use the 4 step process to complete
your answer (State, Plan, Do Conclude.)