design.dichotomous {fat2Lpoly}

Setting-up the design matrix for a logistic model with two biallelic markers.

Description

This function sets up two identical lists, each containing a design matrix for the linear predictor of the logit of a dichotomous outcome under a full logistic model with main effects and product terms for two biallelic markers.

Usage

design.dichotomous(x,...)

Arguments

x

A 2-column matrix of numeric values representing genotypes of biallelic markers, with one column per marker and one row per subject. The two homozygous genotypes must be coded 0 and 1, and the heterozygous genotype value depends on the genetic model: 0 (recessive), 1/2 (allelic) or 1 (dominant).

...

Additional arguments will be ignored, but must be allowed for compatibility with other design functions.

Details

The linear predictors (without intercept) of the logistic function for Y = 1 against the reference level Y = 0 has the form:

\eta_{11} X_{1} + \eta_{12} X_{2} + \eta_{13} X_{1} X_{2}

The design matrix for the above model is constructed by this function.

Value

x.e

List containing the single design matrix with all terms forming the full 2-locus logistic model

x.loc.e

list of character strings containing the indices of the variables in x involved in each term of the logistic model

x.l

identical to x.e

x.loc.l

identical to x.l

Author(s)

Alexandre Bureau <[e-mail]>

See Also

fat2Lpoly, design.full