Computes adjusted Wald confidence interval for a linear contrast of population proportions in a between-subjects design.
Arguments: - alpha: alpha level for 1-alpha confidence - f: vector of sample frequency counts - n: vector of sample sizes - c: vector of contrast coefficients
Values: - estimate, standard error, lower limit, upper limit
alpha = .05
f = c(26, 24, 38)
n = c(60, 60, 60)
c = c(-.5, -.5, 1)
ci.lc.prop.bs(alpha, f, n, c)
## Estimate SE LL UL
## [1,] 0.2119565 0.07602892 0.06294259 0.3609705
Computes sample size per group required to estimate a linear contrast of proportions in between-subjects design with desired precision.
Arguments: - alpha: alpha level for 1-alpha confidence - p: vector of proportion planning values - c: vector of contrast coefficients - w: desired confidence interval width
Values: - required sample size
alpha = .05
p = c(.25, .30, .50, .50)
c = c(.5, .5, -.5, -.5)
w = .2
size.ci.lc.prop.bs(alpha, p, c, w)
## [,1]
## [1,] 87
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