Historically, the exam scores of STAT2606 is approximately normally distributed with a mean of p, = 65 and a standard deviation of or = 15. the exam distribution of STATZGDIS, what is the minimum exam score needed to be accepted? (e) If we take a random sample of 40 students from this population, what is the probability that the average grade of these students is between 60 and 70? (f) If the distribution of exam scores of STAT2606 is positively skewed, would the answer in part (e) still be valid? Justify