4. The following distribution gives the pattern of overtime work done by employees of a company. Calculate: Overtime( Hours) 10-15 15-20 20-25 25-30 30-35 35-40 Number of Employees 11 20 35 20 8 6 (a) The geometric mean (b) The mode of the distribution (c) Harmonic mean (d) Variance of the distribution (e) Obtain the Karl Pearson's coefficient of skewness and comment on the results. (f) Obtain the moment-coefficient of Kurtosis of the overtime data and interpret the results