tau {ResearchMethods}R Documentation

Finding the non-centrality parameter

Description

An iterative, brute-force function to calculate the non-centrality parameter of the chi-sqaured distribution required to achieve the given power and significance level.

Usage

  tau(k,alpha,beta)

Arguments

k degrees of freedom
alpha The significance level
beta 1-power

Details

This function is designed for the calculation of sample sizes in survival analysis. It calulates the non-centrality paramater of a chi-sqaured distribution, given the significance, power and degrees of freedom.

Value

A scalar value representing the non-centrality paramter is returned.

Author(s)

Mohamed Abdolell <mohamed.abdolell@dal.ca> and Sam Stewart <samstewart11@gmail.com>

References

Makuch, Robert W. and Simon, Richard M. “Sample Size Requirements for Comparing Time-To-Failure Among k Treatment Groups”. Chron Dis. 35. pg 861-867/ 1982.


[Package ResearchMethods version 1.01 Index]