f {clippda} | R Documentation

## A function to compute adjustments for the effct of covariates (Z values) for an experiment with a binary exposure and a binary confounder

### Description

A function to compute the Z values when planning an experiment with a binary exposure and a binary confounder. You input the probabilities of 3-cells of the resulting multinomial distribution.

### Usage

    f(x, y, z)

### Arguments

`x` | Proportion of elements in cell 1 of a multinomial population with four cells.
`y` | Proportion of elements in cell 2 of a multinomial population with four cells.
`z` | Proportion of elements in cell 1 of a multinomial population with four cells. The z here is different from the Z which contains information on the effect of covariates and data imbalance on sample size.

### Value

It returns a single real number (greater than or equal 2), representing Z.

### Author(s)

Stephen Nyangoma

### 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)

### See Also

The function ZvaluesformultinomialPlots

### Examples

    # for a 1:1:1:1 experiment
    x=.25;y=.25;z=.25

    # compute Z
    Z=f(x,y,z)
    Z
    ## The function is currently defined as
    function (x,y,z) {
    Z=(1-x-z)*(x+y)/(2*(((1-x-z)*(1-x-y)*(1-y-z))-(1-x-y-z)^2))
    Z
      }

[Package clippda version 1.44.0 Index]