Sample size for a between-subjects proportion linear contrast confidence interval

Computes the sample size in each group (assuming equal sample sizes) required to estimate a linear contrast of population proportions with desired confidence interval precision in a between-subjects design. Set the proportion planning values to .5 for a conservatively large sample size.

Usage

size.ci.lc.prop.bs(alpha, p, w, v)

Arguments

alpha: alpha level for 1-alpha confidence
p: vector of proportion planning values
w: desired confidence interval width
v: vector of between-subjects contrast coefficients

Value

Returns the required sample size for each group

Examples

p <- c(.25, .30, .50, .50)
v <- c(.5, .5, -.5, -.5)
size.ci.lc.prop.bs(.05, p, .2, v)
#>  Sample size per group
#>                     87

# Should return:
# Sample size per group
#                    87