A group of 66 randomly selected students have a mean score of 22.4 with a standard deviation of 2.8 on a placement test. What is the 90% confidence interval for the mean score, μ, of all students taking the test? 21.5 < μ < 23.3 21.8 < μ < 23.0 21.6 < μ < 23.2 21.7 < μ < 23.1
