Question

概率统计问题，详解：

Answer 1

利用已知条件与联合概率表简要分析如图，答案是A。经济数学团队帮你解答，请及时采纳。谢谢！

Answer 2

P(X1X2 = 0) = 1 的意思是：X1、X2至少有一个为零。
所以，当 X1 = -1 或 1 时，X2 = 0
当 X2 = -1 或 1 时，X1 = 0

所以，若要 X1 = X2，只能是 X1 = X2 = 0
所以：P(X1 = X2) = P(X1 = X2 = 0)
P(X2 = 0) = P(X1 = -1, X2 = 0) + P(X1 = 0, X2 = 0) + P(X1 = 1, X2 = 0)
由前所述：当 X1 = -1 或 1 时，X2 = 0，也就是：
P(X1 = -1, X2 = 0) = P(X1 = -1) = 1/4
P(X1 = 1, X2 = 0) = P(X2 = 1) = 1/4
所以：P(X2 = 0) = 1/4 + P(X1 = 0, X2 = 0) + 1/4
解得：P(X1 = 0, X2 = 0) = 0

所以：P(X1 = X2) = P(X1 = X2 = 0) = 0
选A。