twinan90 {gap} | R Documentation |
Classic twin models
The function also allows for test for normality and Box-Cox transformation. It further allows for output data in FISHER format.
twinan90(mzdat,dzdat,vname='mzdz',xlamb=1,const=0,vmiss=-9,path=1, ped=0,nvar=1,form='((1x,a1,5x,F6.2))')
mzdat |
two columns of data for MZ twins |
dzdat |
two columns of data for DZ twins |
vname |
variable name |
xlamb |
the Box-Cox transformation parameter |
const |
constant to be added to each data value |
vmiss |
missing value indicator |
path |
path analysis to be conducted |
ped |
if 1, to output data in FISHER format |
nvar |
number of variables in the data file |
form |
the Fortran format for the data file |
The returned values is in a list with the following components, while the MLEs are in two system files (.log and .out):
h2 |
The heritability estimate based on 2(rMZ-rDZ), where rMZ and rDZ are the intraclass correlation coefficients for MZ and DZ twin pairs |
seh2 |
The standard error for the above statistic |
nMZ |
The number of MZ pairs used |
nDZ |
The number of DZ pairs used |
rMZ |
The intraclass correlation for MZ |
rDZ |
The intraclass correlation for DZ |
covMZ |
The variance-covariance matrix for MZ |
covDZ |
The variance-covariance matrix for DZ |
vname.log |
the diagnostic file |
vname.out |
the output file |
Williams CJ, Christian JC, Norton JA Jr. (1992) TWINAN90: A FORTRAN program for conducting ANOVA-based and likelihood-based analyses of twin data. Computer Methods and Programs in Biomedicine 38:(2-3):167-176
Williams CJ (1993). On the covariance between parameter estimates in models of twin data. Biometrics. 49(2):557-68
built on newtw5.for
Chris Williams, Jing Hua Zhao
## Not run: filespec <- file.path(.path.package("gap"),"tests/mzdz.dat") mzdz <- matrix(scan(filespec,skip=1),ncol=2,byrow=T) mzdat <- mzdz[1:131,] dzdat <- mzdz[132:206,] twinan90(mzdat,dzdat,xlamb=2) # the normality test can be conducted as follows, ks.test(mzdat,"pnorm") ks.test(dzdat,"pnorm") qqnorm(mzdat) qqnorm(dzdat) ## End(Not run)