例1抛掷均匀硬币，令[1,出正面，X=[0,出反面.求随机变量X的分布函数1解P(X =1) = P(X = 0) = 2'x01当x<0时，=0;F(x) = P(X ≤x)
例1 抛掷均匀硬币, 令 = 0, . 1, , 出反面 出正面 X 求随机变量 X 的分布函数. 解 P X{ 1} = = = P X{ 0} , 2 1 = • 0 • 1 x 当 x 0时, F x P X x ( ) { } = = 0;
x01当0≤x<1时,F(x) = P(X≤x}= P(X = 0) 2当x≥1时，0,x<0,F(x) = P(X ≤ x)1= P(X = 0)+ P(X = 1) 0≤x<1,得 F(x):2'1.[1,x ≥1.122
• 0 • 1 x 当 0 x 1时, F(x) = P{X x}= P{X = 0} ; 2 1 = 当 x 1时, F(x) = P{X x} = P{X = 0}+ P{X = 1} 2 1 2 1 = + = 1. = 1, 1. , 0 1, 2 1 0, 0, ( ) x x x 得 F x