search for: s_pooled

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2007 Nov 07
1
Homework help: t test hypothesis testing with summarized data?
Is this how a t hypothesis test is done when I don't have the actual data, but just the summarized statistics: > #Homework 9.2.6 [1] > n<-31 > xbar<-3.10 > s_x<-1.469 > m<-57 > ybar<-2.43 > s_y<-1.35 > s_pooled<- (((n-1)*s_x^2) + ((m-1)*s_y^2)) / (n + m - 2) > s_pooled [1] 1.939521 > t_obs <- (xbar - ybar) / (s_pooled * (sqrt(1/n + 1/m))) > t_obs [1] 1.547951 > qt(c(.025, .975), n+m-2) [1] -1.987934 1.987934 > # Therefore, fail to reject H0 at the 0.05 level of significance > Or...