【判断题】传热方程式中的 称为传热系数,单位是 。
【多选题】(2分)在回归分析中,关于估计标准误差正确的是( )
A.
估计标准误差大,回归直线代表性小,因而回归直线实用价值也小
B.
估计标准误差大,回归直线代表性大,因而回归直线实用价值小
C.
估计标准误差大,回归直线代表性小,因而回归直线实用价值大
D.
估计标准误差可以看作排除x对y影响后,y随机波动大小的估计量
【单选题】Question 6
A.
Because she doesn't want to spend too much money.
B.
Because most of the places have already been taken.
C.
Because there aren't many places to choose from in that area.
D.
Because all the new students are looking for accommodation.
【单选题】My little brother is sleeping. Please don't_____. [ ]
【单选题】奥氏体钢与低碳钢焊接时,若选用的焊条金属合金化程度不够高或者熔合比很大,焊缝金属以及凝固过渡层将容易形成 ( ) 组织。