Amy 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%. Which of the changes below would result in the highest power for her test? (a) Increase the significance level to a = 0.10 and use a sample size of n = 150 Page 3 of 15 (b) Increase the significance level to a = 0.10 and use a sample size of n = 300 (c) Decrease the significance level to a = 0.01 and use a sample size of n = 150 (d) Decrease the significance level to a = 0.01 and use a sample size of n. = 300