设(X,Y)~N( 0, 1, 4, 9, 1/4 ),则X与Y的协方差为? 3/21/23/49 设(X,Y)~N( 0, 1, 4, 9, 1/4 ),则X与Y的协方差为? 3/21/23/49 发布时间:2025-02-23 14:43:08