2. (20 points) Calculate the standard score of 3 students on a class exam given in the following; StudentA=77, StudentB=8, StudentC=34 . The grade system and student marks are given as follows: 5% of the students is going to receive AA, 10% is BA, 16% is BB, 19% is CB, 19% is CC, 16% is DC, 10% is DD and 5% is FF. grades {36, 21, 50, 32, 34, 16, 8, 21, 27, 20, 12, 29, 35, 40, 77, 28, 26, 24, 65, 25, 18, 26, 89, 64, 69, 40, 9, 70, 11, 13, 46} use standard normal distribution. (hint= standard deviation:21.25)