Juan wants to compare the effectiveness of two drugs in treating migraines. he administers drug a to a participant and then drug b to the same participant eight hours later when drug a is still in the participant's system. in this case, the study is contaminated by a effect.

What was the french and indian war about

How will you raise money to equip an army and build a navy. mention specific ideas

Martha participates in a research study in order to receive extra credit for her psychology class. when she arrives in the research office she is given a can of what looks and tastes like beer, but which actually contains no alcohol. in the adjoining room martha's classmate karen is also participating in the study. karen receives a can of alcoholic beer. if the experiment was designed to test the effects of alcohol on concentration, then who is exposed to the independent variable?