Joint distribution of weather conditions and commuting

Question

Joint Distribution of Weather Conditions and Commuting Times

                                 Rain (X=0)                    No Rain (X=1)               Total

Long Commute (Y=0)	0.15	0.07	0.22
Short Commute (Y=1)	0.15	0.63	0.78
Total	0.30	0.70	1.00

Use the probability distribution given in Table 2.2 to compute (a) E(Y) and E(X); (b) σ²_x and σ²_Y; and (c) σ_XY and corr(X,Y).