3. The annual before-tax earnings for a random sample of a company's employees,measured in £000s, are: 35,26,22,24,21,57,36, 35, 29,47,30and36. (a) Carefully construct a boxplot of the data. (The boxplot can

be drawn on ordinary paper - no graph paper needed. The boxplot does not need to be exactly to scale,but values of box properties and whiskers should be clearly labelled.) (b) Given the following summary statistics of the above data: \sum_{i=1}^{12} x_{i}=398 \text { and } \sum_{i=1}^{12} x_{i}^{2}=14,418 calculate the sample standard deviation. You should show your full working. (c) In general, which measure of central tendency would you recommend for earnings data? Briefly justify your choice.