A researcher wants to determine if their new medicine can prevent onset of manic episode in bipolar I with psychotic features. The researcher invited 36 bipolar patients to participate who were on the verge of manic episode. 18 people were assigned in the experimental condition (received medication), another 18 were controls (placebo). After two weeks of taking the medication, symptoms were measured on a scale from 1 - 10 (where 1 - no symptoms to 10 - highly symptomatic). First group showed on average no to mild manic symptoms, whereas the controls had higher symptomatology occurrence on average. Alpha = .01. Experimental: [2, 3, 3, 1, 1, 3, 6, 3, 4, 1, 3, 4, 3, 4, 5, 5, 4, 2]

Control: [8, 9, 7, 6, 9, 8, 6, 4, 5, 9, 6, 6, 5, 8, 6, 4, 9, 8]