四组等级资料比较宜采用
A.t检验
B.X2检验
C.秩和检验
D.u检验
E.t'检验
参考答案:C
—How was your trip?
— . I hope I can go there again.
A.Just so-so
B.Not very good
C.Nothing special
D.Wonderful
对于低压流体输送钢管及管件作外观质量检验,检验项目有哪些