Hello, I ran a growth curve model with individually varying times of observation and am wondering how to interpret the results in terms of units of time. My time variable is hours from birth and my dependent variable is attention/orientation. Since I am not setting any specific time unit, could I say that hours from birth is my unit such that an hour increase in birth results in a beta change in attention?
Yaoyue Hu posted on Thursday, December 12, 2013 - 11:59 am
I am running a growth curve model of 4 time-point data with individually varying time of observation. In this case, chi-square cannot be calculated as the covariance matrices could be held constant across individuals.
However, given loglikelohood, AIC and BIC, how could I tell which model fits the data better, the linear growth curve model or the non-linear model (add a quadratic growth factor)?
2.When I fitted an unconditional non-linear growth curve model, the linear slope is not significant but the quadratic slope is. Further adding covariates into the non-linear model, neither linear slope nor quadratic slope is significant any more. Should I choose the model, the linear or non-linear, based on unconditional model or conditional one?