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.

For more details, see Section 2.22 of Bonett (2021, Volume 3)

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

References

Bonett DG (2021). Statistical Methods for Psychologists https://dgbonett.sites.ucsc.edu/.

Examples

p <- c(.1, .2, .2, .3)
v <- c(.5, -.5, .5, -.5)
size.ci.lc.prop.bs(.05, p, .2, v)
#>  Sample size per group
#>                     60

# Should return:
# Sample size per group
#                    60