1. It has been suggested that physicians may examine women who use oral contraceptives more often or more thoroughly than woman who do not. If so, and if an association is observed between phlebitis and oral contraceptive use, the association may be due to:
a) Selection bias
b) Interview bias
c) Surveillance bias
d) Nonresponse bias
e) Recall bias
ANSWER: ____
2. A randomized trial comparing the efficacy of two drugs showed a difference in the two (with a P valve < 0.05). Assume that in reality, however, they don’t differ. This is therefore an example of:
a) Type I error (alpha error)
b) Type II error (beta error)
c) 1-alpha
d) 1-beta
e) None of the above
ANSWER: ____
3. The major purpose of random assignment in a clinical trial is the...
a) Help ensure that study subjects are representative of the …
b) Facilitate double blinding (masking)
c) Facilitate the measurement of outcome variables
d) Ensure that the study groups have comparable baseline …
e) Reduce selection bias in the allocation of treatment
ANSWER:___