Question

From previous studies, the population standard deviation for a placement test has been determined to be 12.4. The test is
scored on a scale of 0 - 100. A placement agency wants to be 90% confident that the average test score of a sample falls
within plus or minus 3 points of the population average score. How large a sample should be selected ?​

Answer 1

Answer:

I've no idea what ur talking bout