Two events A and B are independent if and only if their joint probability equals the product of their probabilities:

http://en.wikipedia.org/wiki/Independence_(probability_theory)
第2個我不太肯定, 但你可以參考下
P(Sourthern) = 0.24+0.04+0.12 = 0.4
P(Northern) = 0.18+0.12+0.30= 0.6
P(R) = 0.24+0.18= 0.42
P(I) = 0.04+0.12=0.16
P(D)=0.12+0.3=0.42
Given that P (South and R) = 0.24
It is not equal to P(South) X P(R) = 0.4 X 0.42=0.168
Conclusion, They are not independent.