[求助]请教一道逻辑推理题（假设）

xzhang49032

请教一道逻辑推理题（假设）

A researcher discovered that people who have low levels of immune-system activity tend to score much lower on tests of mental health than do people with normal or high immune-system activity. The researcher concluded from this experiment that the immune-system protects against mental illness as well as against physical disease.

The researcher's conclusion depends on which of the following assumptions?
(A) High immune-system activity protects against mental illness better than normal immune-system activity does.
(B)  Mental illness is similar to physical disease in its effects on body system.
(C) People with high immune-system activity cannot develop mental illness
(D) Mental illness does not cause people's immune-system activity to decrease.
(E) Psychological treatment of mental illness is not as effective as in medical treatment

答案是 D
能否解释一下为什么选D？ 十分感激！！！！

vely301

題目是說:低免疫系統level的人會得到比高免疫或正常免疫系統的人還要高分數的mental health test

這個研究建立在免疫系統會保護mental和physical免於疾病

不過 這個要在D假設成立下才會得到這個結論

D是說:mental疾病不會導致免疫系統降低

因為如果免疫系統降低了 那就得不到原研究結論了

所以他要假設mental illness不會影響免疫系統

請NN指教^^

johnyin

A only discussed High immune-system,ommiting the medium and low systems.

B The similarity of mental disease and physical illness cannot draw a conclusion that the immune-system could protect them both.

C The same to A;Whether the system could develop mental illness is irrelavent.

E The effection of medical treatment is not discussed here.

D The best answer,makes it clear that the low immune system is not caused by the mental illness and thus clarifies the roles played by immune system and mental illness: the mental illness is not the reason of low immune system,so supports the conclusion.

xzhang49032

感谢拉！