1. The problem statement, all variables and given/known data On average, 2.5 telephone calls per minute are received at a corporation's switchboard. Making appropriate assumptions about the distribution ( provide justification ), find the probability that at any given minute there will be more than 2 calls. 2. Relevant equations No idea. 3. The attempt at a solution No idea. 1. The problem statement, all variables and given/known data Let the joint p.d.f of X and Y, f(x,y), be given by ..................x ............1.....2.....3 y..1.....0.3..0.2..0.1 ....2 ....0.1..0.1..0.2 (ignore the dots) a) Determine marginal densities b) compute the means and variances of X and Y c) Calculate sigma(?) xy = cov (X,Y) and the correlation coefficient ρ. Are X and Y independent ? d) Let Z = X+Y. determine k(z)+P(Z=z), z = 2,3,4,5. determine the mean and variance. 2. Relevant equations good question 3. The attempt at a solution I don't have one Well, how do I do this? I do not understand it. If anybody has some insight on either problem, I'd appreciate it.