Contrasts: Estimate Contrasts for Mixor Object
In mixor: Mixed-Effects Ordinal Regression Analysis

Description Usage Arguments Value Author(s) See Also Examples

This function is used to specify and estimate contrasts of interest for a mixor object.

1 2	Contrasts(fit, contrast.matrix, digits=max(3, getOption("digits") - 2), signif.stars=TRUE, dig.tst = max(1, min(5, digits - 1)))

`fit`	A `mixor` object.
`contrast.matrix`	A matrix of contrasts of interest. Each column in the contrast matrix should be of the same length as the `coef` vector of the fitted `mixor` object.
`digits`	minimum number of significant digits to be used for most numbers.
`signif.stars`	logical; if TRUE, P-values are additionally encoded visually as "significance stars" in order to help scanning of long coefficient tables.
`dig.tst`	minimum number of significant digits for the test statistics.

A list containing the following components:

`contrast.matrix`	a matrix specifying the contrasts of interest.
`Contrasts`	a matrix containing the estimates, SEs, Z-values, and p-values for the contrasts of interest.

Kellie J. Archer, Donald Hedeker, Rachel Nordgren, Robert D. Gibbons

See Also as mixor, coef.mixor, vcov.mixor

library("mixor")
data("SmokingPrevention")
# data frame must be sorted by id variable
SmokingPrevention<-SmokingPrevention[order(SmokingPrevention$class),]
Fitted.students<-mixor(thksord~thkspre+cc+tv+cctv, data=SmokingPrevention, 
     id=class, link="logit")
summary(Fitted.students)
coef(Fitted.students)
vcov(Fitted.students)
cm<-matrix(c(-1,-1,-1,0,0,0,0,0,
              0, 0, 0,0,0,0,0,0,
			  0, 0, 0,1,0,0,0,1),ncol=3,byrow=TRUE)
Contrasts(Fitted.students, contrast.matrix=cm)

Loading required package: survival

Call:
mixor(formula = thksord ~ thkspre + cc + tv + cctv, data = SmokingPrevention, 
    id = class, link = "logit")

Deviance =         4230.766 
Log-likelihood =  -2115.383 
RIDGEMAX =         0 
AIC =             -2123.383 
SBC =             -2135.004 

                    Estimate Std. Error z value   P(>|z|)    
(Intercept)         0.075750   0.153514  0.4934  0.621701    
thkspre             0.414797   0.040822 10.1612 < 2.2e-16 ***
cc                  0.861324   0.187239  4.6001 4.222e-06 ***
tv                  0.205859   0.168025  1.2252  0.220510    
cctv               -0.301123   0.251755 -1.1961  0.231660    
Random.(Intercept)  0.188630   0.066243  2.8476  0.004406 ** 
Threshold2          1.273406   0.062949 20.2293 < 2.2e-16 ***
Threshold3          2.478912   0.080216 30.9029 < 2.2e-16 ***
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
       (Intercept)            thkspre                 cc                 tv 
        0.07575035         0.41479744         0.86132413         0.20585925 
              cctv Random.(Intercept)         Threshold2         Threshold3 
       -0.30112255         0.18862954         1.27340629         2.47891177 
                     (Intercept)       thkspre           cc            tv
(Intercept)         2.356667e-02 -0.0033425314 -0.016115374 -1.554730e-02
thkspre            -3.342531e-03  0.0016664078  0.000215435 -1.005232e-04
cc                 -1.611537e-02  0.0002154350  0.035058258  1.558126e-02
tv                 -1.554730e-02 -0.0001005232  0.015581257  2.823231e-02
cctv                1.425335e-02  0.0009160829 -0.033842031 -2.793812e-02
Random.(Intercept) -8.011787e-05  0.0002697499  0.001749551 -1.948124e-03
Threshold2         -1.793964e-04  0.0008120776  0.001349416  8.913283e-04
Threshold3          2.950014e-04  0.0010213593  0.000698184  4.116407e-05
                            cctv Random.(Intercept)    Threshold2   Threshold3
(Intercept)         0.0142533511      -8.011787e-05 -0.0001793964 2.950014e-04
thkspre             0.0009160829       2.697499e-04  0.0008120776 1.021359e-03
cc                 -0.0338420310       1.749551e-03  0.0013494164 6.981840e-04
tv                 -0.0279381163      -1.948124e-03  0.0008913283 4.116407e-05
cctv                0.0633804946       1.241640e-03 -0.0003811800 1.260757e-03
Random.(Intercept)  0.0012416404       4.388076e-03  0.0006060819 1.702859e-03
Threshold2         -0.0003811800       6.060819e-04  0.0039625142 3.838976e-03
Threshold3          0.0012607567       1.702859e-03  0.0038389758 6.434629e-03
                    1  2  3
(Intercept)        -1 -1 -1
thkspre             0  0  0
cc                  0  0  0
tv                  0  0  0
cctv                0  0  0
Random.(Intercept)  0  0  0
Threshold2          0  1  0
Threshold3          0  0  1


  Estimate Std. Error z value   P(>|z|)    
1 -0.07575    0.15351 -0.4934    0.6217    
2  1.19766    0.16700  7.1717 7.405e-13 ***
3  2.40316    0.17150 14.0128 < 2.2e-16 ***
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1