P{1<X≤2}=F(2)-F(1)=1-0.9=0.1 或 =P{X=2}. F(0.5=03, P{X=0.5}=0 0.9 0.3P{1 X  2} P{X = 0.5}= 0. = F(2) − F(1) = 1 − 0.9 = 0.1 = P{X = 2}. 或 F(0.5) = 0.3, O 1 2 x 0.3 0.9 1