The scores on Act college entrance examination in current year had the normal distribution with mean μ = 18.6 and standard deviation σ = 5.9
a) Determine the probability that a single student randomly selected from all those taking the test scores 21 or higher?
b) The average score of the 76 students at Northside High who took the test as x =20.4. Determine the probability that the mean score for 76 students randomly selected from all who took test nationally is 20.4 or higher?