An accountant of a manufacturing company was interested in the time (weeks) that the company took to pay its suppliers, The accountant took a sample of invoices and recorded the payment time, then used Excel to create the following: Payment time Mean 5.02 Standard Error 0.31 Median 6 Mode 8 Standard Deviation 2.53 Sample Variance 6.42 Range 7 Minimum 1 Maximum 8 Sum 326 Count 65 a) Is this categorical or quantitative data? Briefly explain. b) State the symbol that represents the standard deviation for this data set (use words if necessary). c) Is this data set negatively skewed, positively skewed or symmetric? Briefly explain your reasoning. d) Briefly state the best measure of centre for this data set