Supposed we have observed the following returns associated with a common share during the past six years (r=historical returns): Year Rt Year Rt 2017 16% 2014 20% 2016 13% 2013 17% 2015 -5% 2012 23% a. Calculate the arithmetic, or simple, average of annual returns earned during the last six (6) years. (5 Marks). Estimate the risk associated with the share by estimating the standard deviation of returns