(a) What criteria do you apply to judge the merits of an average? Describe the manner of computations of any three averages with suitable illustrations. (b) Calculate coefficient of variation from the following data relating to production of a steel mill on 60 days. Production (in Tons per day): 21-22 23-24 25-26 27-28 29-30 Number of days: 7 13 22 10 (a) Define weighted average and explain how it differs from simple mean. Give the method of its computations and discuss the use of weighted mean in Statistics. (b) Find the missing age in the following set of four student ages. Student Age Deviation from the Mean A 19 4 B 20 C D