NO.PZ2015120604000089
问题如下:
According to the research, 65% of all companies have a scanner. Assuming we selected 8 companis, what is the probability that five companies would have a scanner ?
选项:
A.0.138.
B.0.311.
C.0.279.
解释:
C is correct.
[8!/5!(8- 5)!](0.65) 5 (0.35) 8 - 5 = 56*(0.1160)*(0.04288) =0.279.
题目应该改成65% of all companies have scanners.... what is the probability that all five companies would have scanners ,否则读起来有歧义