I have 12 data points (T1-T12) and would like to model for potential cubic growth in GMM. I managed to fit a decent linear and quadratic growth models but am unclear on to determine the appropriate times in the syntax for a cubic model:
Thanks for the quick response. Can you clarify exactly what you mean though. As shown in my initial post I already have four growth factors listed (i s q cub) before the "|" symbol, but I am unclear on what I should list after the "@" symbol for each of the 12 time points. Thank you for your explanation.
You list the linear time scores after the | symbol. I just noticed you did this incorrectly for the quadratic model. The time scores are always the linear and Mplus computes the others. Keep the on a small scale like 0 .1 .2 etc.
I have 7 data points and would like to investigate various forms of growth (linear, quadratic, cubic). I wondered what would be the best way to do this, that is: is there a specific order to introduce the various growth factors? So first try linear, than linear and quadratic, and so on? (and then check whether mean and variance of the growth factors are different from zero) Or should I be guided by other things?