84. A scientist is designing a clinical trial to test the effect of online chat counseling with migraine sufferers as a supplementary treatment in combating their migraines. Migraine sufferers will have access to counselors via online chat software; the scientist plans to see whether their migraine pain has been reduced after six weeks. Preliminary information suggests that the effect of (face-to-face) counseling is larger for migraine sufferers who are women than men. Knowing this, the scientist would probably use a A) stratified random sample. B) completely randomized design. C) block design, with counseling and no counseling as the blocks. D) block design, with women and men as the blocks. 85. A scientist is designing a clinical trial to test the effect of online chat counseling with migraine sufferers as a supplementary treatment in combating their migraines. Migraine sufferers will have access to counselors via online chat software; the scientist plans to see whether their migraine pain has been reduced after six weeks. The subjects would obviously know whether or not they were given access to the counseling. What experimental technique does this eliminate? A) informed consent B) randomization C) blinding D) confounding