library(DGB)
Compute confidence interval for a ratio of population means of ratio-scale measurements in a 2-group design. Equality of variances is not assumed.
Arguments: - alpha: alpha level for 1-alpha confidence - y1 vector of scores for group 1 - y2: vector of scores for group 2
Values: - means, mean ratio, lower limit, upper limit
alpha = .05 group2 = c(32, 39, 26, 35, 43, 27, 40, 37, 34, 29, 49, 42, 40) group1 = c(36, 44, 47, 42, 49, 39, 46, 31, 33, 48) ci.ratio.mean.is.data(alpha, group1, group2)
Computes sample size required to estimate a ratio of population means with desired precision in a 2-group design.
Arguments: - alpha: alpha level for 1-alpha confidence - var: planning value of average within-group DV variance - m1: planning value of mean for group 1 - m2: planning value of mean for group 2 - r: desired upper to lower confidence interval endpoint ratio
Values: - required sample size per group
alpha = .05 var = .4 m1 = 3.5 m2 = 3.1 r = 1.2 size.ci.ratio.mean.is(alpha, var, m1, m2, r)
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