Successive weekly sales, in units of one thousand dollars, have a bivariate normal distribution with common mean 40, common standard deviation 6, and correlation .6. (a) find the probability that the total of the next 2 weeks’ sales exceeds 90. (b) if the correlation were .2 rather than .6, do you think that this would increase or decrease the answer to (a)? explain your reasoning. (c) repeat (a) when the correlation is .2.