题目设随机变量X~N(2,4),Y=2X-1,则Y~()A. N(3,7)B. N(3,15)C. N(3,16)D. N(4,8)设随机变量X~N(2,4),Y=2X-1,则Y~()A. N(3,7)B. N(3,15)C. N(3,16)D. N(4,8)题目解答答案C. N(3,16)