NO.PZ2020010301000012
问题如下:
Based on the probabilities in the diagram below, what is the value of the following?
Pr(B|A)
选项:
A. 30%
B. 40%
C. 38%
D. 43.8%
解释:
Pr(B|A) = Pr(A∩B)/Pr(A) = (11% + 10%)/48% = 43.8%
看图的话为啥不是中间交集的两个百分比直接加,先让a发生,在a发生的情况下看看b的哪部分发生