Behavioral Genetics Models
sealx017
Joined: 08/17/2018
Include covariates in multivariate cholesky model
Hi,
I have a dataset of twins on 4 time-points and a covariate which does not vary over time. I can fit the Multivariate cholesky decompositon model with ACE components but stuck at the case where I want to include that covariate at each time-point.
This how I was including the covariate (snp),
defSNP <- mxMatrix( type="Full", nrow=1, ncol=2, free=FALSE, labels=c("data.snp1","data.snp2"), name="snp" ) {note that snp1 corresponds to twin 1 and snp2 corresponds to twin 2)
szellers
Joined: 04/04/2018
Constraining results of an algebra
Hi!
I am trying to constrain the results of an algebra, either to a fixed value or constraining the results of two algebras to be equivalent. I am using https://openmx.ssri.psu.edu//wiki/mxConstraint-help as a starting point.
Example output is attached, but the relevant lines of code are below
I want to fix AlCO[2,2] to 0 in the first example.
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JuanJMV
Joined: 07/20/2016
Moderation doubt
Hi everyone,
I am trying to test if there is a difference in one variable (quantitative) due to another variable (binary but different for each twin).
These variables are related and I want to test if there are different “subtypes” of that disorder (quantitative variable) depending on the value of the other variable (binary variable).
I was thinking to do a moderation analysis (as Rob suggested me in a previous post) as follows:
1-Quantitate variable
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IvanVoronin
Joined: 08/18/2013
Equality constraints in saturated model
What is the better way to introduce the constrains given that the constrained elements are computed, not defined as matrices?
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szellers
Joined: 04/04/2018
Diagnostics for Confidence Intervals
I am estimating a linear latent growth model using two twin samples and I am also estimating a common pathway model in the same samples. The latent slope and intercept are free to correlate with each other and with the latent factor from the common path model. I am trying to compute confidence intervals using mxCI and I am getting errors. When I use the verbose summary, I get the diagnostic and status code of "alpha level not reached iteration limit/blue" on many of my estimates. I've looked around at some documentation/other forum posts.
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JuanJMV
Joined: 07/20/2016
Common and independent models
Hello,
I am trying to fit a trivariate model with 3 continuous variables. I am also trying to fit the independent and common pathways models but I do not know if my script is correct.
My models have:
ADE: 27 parameters
Independent pathway model: 27 parameters
Common pathway model: 24 parameters
I think that number of parameters is correct but I am not sure. Also, I have negative values (for example dl_1_1, fl_2_1) and I do not know if it is correct.
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Kelsey
Joined: 01/31/2017
Bivariate model with binary and continuous variable
Hi,
I am new to bivariate models and I have tried to adapt the twoACEj.R script by Hermine Maes from an ordinal to a binary variable in the below script. The script runs without errors, but my first question is whether my adaptations are correct?
JuanJMV
Joined: 07/20/2016
phenotypic correlation
Hello,
I am a little bit confused about how to calculate the phenotypic correlation between variable 1 and variable 2, in a bivariate model with one binary variable and one continuous variable.
I mean if I use this: mxEval(cov2cor(V), fitADE, T). I get a value of 0.200 whereas if I calculate the correlation in SPSS (also in R) I get a value of 0.150.
I do not know if I am doing something wrong. Should the results be the same right?
I have tried with different methods, with and without covariables etc… But I get the same value.
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Julia
Joined: 03/29/2012
System is exactly singular
Hi all,
I am running a trivariate Cholesky ADE model with one binary and two continuous variables. As profile-based confidence intervals took more than 24h to run and a lot of them were missing I decided to try bootstrapping. I ran mxBootstrap with 1000 replicates to get 95% CI and all looked fine except CI's for dominant genetic correlation rD. I get the following error:
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JuanJMV
Joined: 07/20/2016
Siblings
Hello,
I am trying to do a univariate analysis with a binary variable. I am not sure how to treat siblings
I have created different groups MZ, DZ, SIB (which I think is the same as introduce SIB in the DZ group).
I have also checked if DZ and SIB can be equated through the saturated model and there are not significant differences when I equated means and variances between DZ and Sib
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