Researchers conducted a randomized, double-blind study to measure the effects of the drug olanzapine on patients diagnosed with bipolar disorder. A total of 115 patients with a DSM-IV diagnosis of bipolar disorder were randomly divided

into two groups. Group 1 (n1 = 55) received 5 to 20 mg per day of olanzapine, while group 2 (n2 = 60) received a placebo. The effectiveness of the drug was measured using the Young€“Mania rating scale total score with the net improvement in the score recorded. The results are presented in the table. Does the evidence suggest that the experimental group experienced a larger mean improvement than the control group at the a = 0.01 level of significance?

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Experimental Control Group Group 60 14.8 8.1 Mean improvement Sample standard deviation 12.5 12.7