ztwo: A function to compute Z values when there are no covariates other than the cancer class
Description
This function computes the effects of covariates (Z values) needed when designing a study
in simple cases where the only covariate available is the cancer class. The Z values
computed may, however, be used in more complex setups, when additional covariates are expected.
Usage
ztwo(x, y)
Arguments
x
expected proportion of cases
y
expected proportion of controls
Value
produces the Z value
References
Nyangoma SO, Ferreira JA, Collins SI, Altman DG, Johnson PJ, and
Billingham LJ: Sample size calculations for planning clinical
proteomic profiling studies using mass spectrometry. (Working paper)