2. An investigator examined cases of fetal death in 27,000 pregnancies and classified mothers according to whether they had experienced sexual intercourse within 1 month before delivery. It was found that 11% of the mothers of fetuses that survived had had sexual intercourse during the period. It was concluded that intercourse during the month preceding delivery caused the fetal deaths. This conclusion:

This question is incomplete, here's the complete question.

An investigator examined cases of fetal death in 27,000 pregnancies and classified mothers according to whether they had experienced sexual intercourse within 1 month before delivery. It was found that 11% of the mothers of fetuses that died and 2.5% of the mothers of fetuses that survived had had sexual intercourse during the period. It was concluded that intercourse during the month preceding delivery caused the fetal deaths. This conclusion:

a. May be incorrect because mothers who had intercourse during the month before childbirth may differ in other important characteristics from those who did not

b. May be incorrect because there is no comparison group

c. May be incorrect because prevalence rates are used where incidence rates are needed

d. May be incorrect because of failure to achieve a high level of statistical significance

e. Both b and c

Answer: a. May be incorrect because mothers who had intercourse during the month before childbirth may differ in other important characteristics from those who did not

Explanation:

The conclusion in this example could be considered a single factor fallacy, meaning that the investigation has been largely done around a single factor, missing others that may change the results.

Before reaching that conclusion, other variables should be tested to be sure there aren't other important characteristics that influence the relationship between those mothers' sexual practices and fetal deaths.