Suppose we wanted to test the idea that a control group of cancer patients (Group 1) would report higher mean pain ratings than an experimental group receiving special massage treatments (Group 2). Use the following information to compute a t-statistic for independent groups: mean group 1 = 78.1 SD1 (variance) = 49.1 n1 = 25 mean group 2 = 74.1 SD2 (variance) = 59.7 n2 = 25 What are the degrees of freedom and the value of t? Using α=0.05 for a two-tailed test, is this t statistic significant? Show your calculations for full credit.
Added by Sara A.
Step 1
First, we need to calculate the pooled variance (Sp^2): Sp^2 = ((n1 - 1) * SD21 + (n2 - 1) * SD22) / (n1 + n2 - 2) Sp^2 = ((25 - 1) * 49.1 + (25 - 1) * 59.7) / (25 + 25 - 2) Sp^2 = (24 * 49.1 + 24 * 59.7) / 48 Sp^2 = (1178.4 + 1432.8) / 48 Sp^2 = 2611.2 / 48 Sp^2 Show more…
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