NO.PZ202208220100000403
问题如下：
Determine and justify the potentially influential observations in Exhibit 1 using the criteria for Cook’s D involving k and n.
选项：
A.Observations 6 and 50, because their Cook’s D values exceed 0.144 B.Observations 1，6 and 50, because their Cook’s D values exceed 0.144 C.Observations 1, 6, 50, and 92, because their Cook’s D values exceed 0.100解释：
B is correct. The required criteria for using Cook’s D to identify influential observations is
which implies the ith observation is highly likely to be an influential data point. Since n = 96 and k = 2, then 
= 0.144. observations1, 6 and 50, have a Cook’s D that exceeds 0.144, so they are highly likely to be influential observations.
请问CookD的公式是2*sqrt(k/n)吗？
