Vpo {asht} | R Documentation |
Variance for estimated Mann-Whitney parameter under proportional odds.
Description
A function to calculate the variance of the estimated Mann-Whitney parameter under the proportional odds model.
Usage
Vpo(PHI, tf, ny, nx)
Arguments
PHI |
Mann-Whitney parameter |
tf |
tie factor |
ny |
sample size for the y variable |
nx |
sample size for the x variable |
Details
Uses uniroot to find the variance numerically. The approximation using the LAPH method (Lehmann alternative model combined with the proportional hazards model) is much faster and is the default.
Value
the variance of the estimated Mann-Whitney parameter
Examples
Vpo(.7,.8,5,7)
## Compare to LAPH method
VLAPH<- function(PHI,tf=tiefactor,ny=n.y,nx=n.x){
tf*(PHI*(1-PHI)/(ny*nx))*
(1+((ny+nx-2)/2)*
((1-PHI)/(2-PHI)+PHI/(1+PHI)))
}
VLAPH(.7,.8,5,7)
[Package asht version 1.0.1 Index]