Question Three a. The weights of numbers of students were recorded in kg. Weight(kg) 30 - 35 35 - 40 40 - 45 45 - 50 50-55 Frequency 10 11 15 7 4 i. Calculate the mean. ii. Calculate the mode. iii. Calculate the median. iv. Calculate the interquartile range. (11 mars) b. The marks obtained by a set of students in an examination are given below: Marks 5 10 15 20 25 30 No. of Students 6 4 6 12 X 4 i. Find the value of x given that the mean value of the set is 18. (6 marks) ii. What is the probability of a student scoring at least 20 in the test