bc.twocomp: bc.twocomp In bimixt: Estimates Mixture Models for Case-Control Data

Description

Implementation of two component models. In the two component unconstrained model, the components of the control and case mixtures are the same; however the mixture probabilities may differ for cases and controls. In the two component constrained model, all controls are distributed according to one of the two components while cases follow a mixture distribution of the two components.

Usage

 ```1 2 3``` ```bc.twocomp(x.cases, x.controls, constrained = T, lambda.bounds = c(-5, 5), control.comp = 1, start.vals=NULL) ```

Arguments

 `x.cases` a numeric vector of case values `x.controls` a numeric vector of control values `constrained` Boolean indicating whether the two component constrained model should be used (default `T`) or the two component unconstrained model should be used (`F`) `lambda.bounds` numeric vector of bounds: `c(upper bound, lower bound)`. Specifies the range for `optim` to search for the optimization of lambda. Default: `c(-5,5)`. `control.comp` indicator of which component contains the controls (1 or 2) `start.vals` starting values for the EM algorithm. If `NA`, the starting values are estimated from the data.

Value

 `lambda` Box-Cox transformation parameter `type` model type ( "2cc" or "2cu") `mu.cases` means of the Box-Cox transformed case components `sig.cases` standard deviations of the Box-Cox transformed case components `pi.cases` proportion of cases in each case component `mu.controls` means of the Box-Cox transformed control components `sig.controls` standard deviations of the Box-Cox transformed control components `pi.controls` proportion of controls in each control component (always equal to 1 for 2cc since all controls are forced into one component) `max.loglike` the maximum log likelihood value for the model `mu.cases.unt` an estimate of the untransformed means of the case components. Based on Monte Carlo simulations. Values will differ by computer seed. `sig.cases.unt` an estimate of the untransformed standard deviations of the case components. Based on Monte Carlo simulations. Values will differ by computer seed. `mu.controls.unt` an estimate of the untransformed means of the control components. Based on Monte Carlo simulations. Values will differ by computer seed. `sig.controls.unt` an estimate of the untransformed standard deviations of the control components. Based on Monte Carlo simulations. Values will differ by computer seed. `case` original case values `control` original control values `time` running time for the model fit

Author(s)

Michelle Winerip, Garrick Wallstrom, Joshua LaBaer

`bc.binorm` `bc.fourcomp` `em.twocomp.m1` `em.twocomp.m2` `em.twocomp.m3`