18. a) Compute the Z score for each of the following exam grades.i) A grade of 79 on a test with an average (x-bar) = 75 and standard deviation(s) = 2ii) A grade of 65 on a test with an average (x-bar) = 60 and standard deviation(s) = 2b) Which of these exams grades has a better relative positive and why?i) A grade of 79 on a test with an average (x-bar) = 75 and standard deviation(s) = 2ii) A grade of 65 on a test with an average (x-bar) = 60 and standard deviation(s) =2
