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Unformatted text preview: numerator ((n1-1)Var1 + (n2- 3140.96 denominato (n1 + n2 -2) 94 Sp2= 33.41 Compute Observed Difference between Two Sample Means (Xbar1 - Xbar2)=-2.83 Next, compute Ttest for Two Sample means: Ho: (MuSupplemen Ttest = (Xbar1-Xbar2) / SQRT(pooled varian-2.4 Pvalue= 0.01 Step 4 Statistical Decision? Statistical DecisionReject the Null, using either decision rule above Step 5 Conclusion? ConclusioMean days of illness for Supplement Group Significantly less than Placebo group Pvalue is less than Alpha (.05), so we can rule out chance. Conclude that taking supplements significantly reduces number of illness days, compared to taking placebo pills (I.e., nothing at all). If a Decision error w could be Type I error. Potential Consequences of such an error? Would approve Supplement Therapy, when in fact, days of illness are not reduced, and may even be increased. Resulting in wasted medical expenses, and greater illness....
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- Spring '07
- Statistics, Null hypothesis, Statistical hypothesis testing, Supplement Therapy, Directional Alternative Hypotheses, Compute Pooled Variance