Stats Question. Please help me with my ignment. Thanks. Please provide some explanation with answers.?

Question 1: Suppose you know that grades igned to a cl of 120 students was normally distributed, with a mean of 70% and a standard deviation of 10. a) How many students would you expect to receive grades of i) Over 80% ii) Over 70% iii) Fail (<50%) b) What if a group of 20 students really focus and as a result their averages increase by 10% (ie a student that before had 75% now gets 85%. uming the grade distribution remains normal and the standard deviation is unchanged, but the mean increases, what would this do to answers (i) to (iii) above? c) If you pick a student at random, knowing only the information above, ie the mean = 70%, standard deviation = 10, and the fact that the grades are normally distributed, what can you about that student’s predicted grade? d) If I asked you to recommend factors (ie information) on each student that would allow you to better predict grades (relative to what can be done in part c above), what would those characteristics include? List at least 5 factors. Guess a ranking – ie. The most important, the second most important and so on.