无心磨削时，导轮的轴线与砂轮的轴线应平行。
参考答案：错
Which of the following methods is used to provide a standard to measure performance
A．Benchmarkin
B．Samplin
C．Estimatin
D．Levelin
当|r|＜1时，通常认为：0＜|r|≤0.3为微弱相关；0.3＜|r|≤0.5为低度相关； 0.5＜|r|≤0.7为显著相关；0.7＜|r|＜1为高度相关。( )
