Patients who are addicted to cocaine or sometimes using the drive to combat pression. as such, sometimes addicts are given antidepressant medications to prevent relapse. a three year study compared the effects of two such medications, lithium and desipramine, along with a placebo for 72 cocaine users wishing to break the habit. the patients were put into three groups of 24, and given one of the three treatments at random. this to a table illustrates the results. according to the table, 10 of the users who took desipramine relapsed. this number is example of a?