An observational study is described. Determine the nature and scope of the conclusion the study can reach.
In a group of 500 women, those who smoked moderately did worse on tests of reaction time than those who did not smoke.
A) Smoking moderately causes women to do worse on tests of reaction time.
B) Since there is no random assignment, there is no way to know that smoking causes subjects to do worse on tests of reaction time; there may have been lurking variables.
C) Since there is no random assignment, there is no way to know that smoking causes subjects to do worse on tests of reaction time; there may have been confounding variables.
D) Smoking moderately causes people to do worse on tests of reaction time.
E) Since the study involved only women, there is no way to know that smoking causes people to do worse on tests of reaction time.
Is B the right answer?
2 answers
Without more data, my best guess would be E.