The scores of high school seniors on ACT college entrance examination in the 2003 has mean = 20.8 and standard deviation = 4.8. The distribution of scores is only roughly normal.
A) What is the approximate probability that a single student randomly chosen from all those taking the test scores 23 or higher?
B) Not take an SRS of 25 students who took the test. What are the mean and standard deviation of the sample mean score xbar of these 25 students?
C) Find out the approximate probability that the mean score xbar of these students is 23 or higher?
D) Which of your tow normal probability calculations ins (a) and (c) is more correct and why?