Are there slope and intercept terms in Gamm?
The gamm () supporting documentation states that the random terms need to be given in the list form as in lme () but I cannot find any interpretable examples that include both slope and intercept terms. Any advice / solutions would be much appreciated.
When to include random slopes in linear mixed effect models?
The subtext for the random intercept model is that we assume (despite there different starting points) that participants respond to time in exactly the same way (in other words, all of the individual participants’ regression lines are parallel). So the important question is: Do we think such an assumption is valid?
How to test for random effects in GAMS?
One of the nice things about the output from the gam () model is that the summary () contains a test for the random effects
How to calculate Grms from a random ASD curve?
Below is presented the method to calculating the root-mean-square acceleration (Grms) response from a random vibration ASD curve. Typical random vibration response curve: Grmsvalues are determined by the square root of the area under a ASD vs. frequency response curve.
How to fit a model with a random intercept?
I have successfully fitted a model with a random intercept using the below code within the mgcv library, but can now not determine what the syntax is for a random slope within the gamm () function:
How to enter random intercept and slope in lmer?
You specify the random intercept and slope in the same way that you do in the lmer style. In your case: Here is the gamm () syntax to enter correlated random intercept and slope effects, using the sleepstudy dataset. The syntax to enter uncorrelated random intercept and slope effects is the same for lme () and gamm ().
How to use gamm4 in the lmer style?
The gamm4 function in the gamm4 package contains a way to do this. You specify the random intercept and slope in the same way that you do in the lmer style. In your case: Here is the gamm () syntax to enter correlated random intercept and slope effects, using the sleepstudy dataset.