AP STATS: HELP? Find the power of the tests? 10 PTS RIGHT AWAY!?
INFO: You want to see if a redesign of a the cover of a mail-order catalog will increase sales. Norm dist, large # of customers, random sample..
-mean will be approx.normal w/ standard deviation of 50 dollars,
-mean for the original catalog will be 25 dollars.
-use a sample size of n = 900.
You wish to test Ho : mean = 25 & Ha: mean > 25
You reject Ho if sample mean is greater than 26 and accept otherwise.
#1 Find the prob that your test rejects Ho when in fact mean = 25. [Type I Error]
(ANSWER: probability is 27.43%)
#2 Find the prob that your test accepts Ho when in fact mean = 28 [Type II Error]
(ANSWER: probability is 11.51%)
Find the actual power of the test from questions #1 and #2.