4.74 Scores on an ex am ination are a ssum ed to be norm ally distributed with mean 78 and variance 36. a. Whatis the probability that a person takingthe ex amination scoreshigher than 72? b. Suppose...

Extracted text: 4.74 Scores on an ex am ination are a ssum ed to be norm ally distributed with mean 78 and variance 36. a. Whatis the probability that a person takingthe ex amination scoreshigher than 72? b. Suppose that students scoring in the top 10% of this distribution are to receive an A grade. What is the m inim um score a student must achieve to eam an A grade? c. Whatmust be the cutoff point for passing the ex am ination if the ex am inerwants only the top 28.1% of all scores to be passing? d. Approx im ately what proportion of studentshave scores 5 or m ore points above the score that cuts off the lowest 25%? e. RStudio Exercise Answer parts(a)(d), using R Studio. f. Ifit is known that a student's score ex ceeds 72, whatis the probability that his or her score ex ceeds 84?