coef.qualint: Extract estimation results from a "qualint" object

Description

Similar to other coef methods, this function extracts the estimation results from an "qualint" object.

Usage

"coef"(object, ...)

Arguments

object

a qualint object

...

not used. Additional print arguments

Value

A numeric matrix (see above). For type = "continuous", it is the estimation results for mean difference. For type = "binary", it is for risk difference, log relative risk or log odds ration. For type = "survival", it is for log hazard ratio.

Details

This function extracts the results related with estimating results of the interaction test from a "qualint" object. It returns a matrix which contains the estimating results of the treatment effects which will used directly in the testing process later. FOr continuous responses, it is the mean difference. For binary responses, it is the risk difference, log relative risk or log odds ratio. For survival responses, it it the log hazard ratio.

References

Gail and Simon (1985), Testing for qualitative interactions between treatment effects and patient subsets, Biometrics, 41, 361-372.

Pan and Wolfe (1993), Tests for generalized problems of detecting qualitative interaction, Technical Report No. 526, Department of Statistics, The Ohio State University.

Pan and Wolfe (1997), Test for qualitative interaction of clinical significance, Statistics in Medicine, 16, 1645-1652.

Examples

Run this code

ynorm <- rnorm(300)
trtment <- sample(c(0, 1), 300, prob = c(0.4, 0.6),
                  replace = TRUE)
subgrp <- sample(c(0, 1, 2), 300, prob = c(1/3, 1/3, 1/3),
                 replace = TRUE)
test1 <- qualint(ynorm, trtment, subgrp)
coef(test1)

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