单选题 A certain airport security scanner designed to detect explosives in luggage will alert the scanner's operator whenever the piece of luggage passing under the scanner contains an explosive. The scanner will erroneously alert the operator for only one percent of the pieces of luggage that contain no explosives. Thus in ninety-nine out of a hundred alerts explosives will actually be present.
The reasoning in the argument is flawed because the argument

A、 ignores the possibility of the scanner's failing to signal an alert when the luggage does contain an explosive.
B、 draws a general conclusion about reliability on the basis of a sample that is likely to be biased.
C、 ignores the possibility of human error on the part of the scanner's operator once the scanner has alerted him or her.
D、 fails to acknowledge the possibility that the scanner will not be equally sensitive to all kinds of explosives.
E、 (E) substitutes one group for a different group in the statement of a percentage.

【正确答案】 E

【答案解析】[解析] 本题依据扫描器检查无爆炸性物质的行李的准确率为99%，而作出了扫描器检查含有爆炸性物质的行李的成功率也是99%的结论，因此本题的论述很显然犯了(E)所陈述的推理错误。