Question B2 The scores of Economics examination in last year were released and the average was 55 marks while the standard deviation was 12 marks. Assume normal distribution. a What is the probability that a randomly selected student has the score below 40 marks? (3 marks) b) If the Economics teacher issued certificates to 4% of the students having the highest scores during this examination, what is the lowest score among the students who got the certificates? (2 marks) c) What is the probability that a randomly selected student has the score between 50 and 59 marks? (2 marks) d) Calculate the total number of students taking this examination, given that 36 of them had the scores above 75 marks. (3 marks) (Total 10 marks)