5. An advertising company recorded the weekly sales (in Ringgit Malaysia - RM) data for their two executive, Mark and Adam. Seven weeks data were recorded and shown in Table 1. Table 1 Week Mark Adam 1 2188 1986 2 2252 2474 3 2473 2346 4 2126 1825 5 2420 2127 6 2226 2265 7 2211 2573 a) Calculate the standard deviation for the dataset. (4 Marks) b) Which executive is more consistent in their sales? Explain your answer. (2 Marks)