Question

Asha owns a car-wash and is trying to decide whether or not to purchase a vending machine so customers

can buy coffee while they wait. She'll get the machine if she's convinced that more than 30% of her
customers would buy coffee. She plans on taking a random sample of n customers and asking them
whether or not they would buy coffee from the machine, and she'll then do a significance test using
a = 0.05 to see if the sample proportion who say "yes" is significantly greater than 30%.
Suppose that in reality, it is actually 33% of her customers that would buy coffee.
Which of the changes below would result in the highest power for her test?

Answer 1

Answer: D

Explanation:

She uses a sample size of n=200, and 50% of all customers would actually buy coffee.