Hi everyone
I have to regress some covariates on a set o states (0, 1, 2), using a multinomial logit. Assume now that each array of observations (one array for each covariate), is composed by several time series. So each considered country provides a time series for covariate, then the time series are ordinately put inside the same array (accurately checking for each associated date).
Is necessary to standardize data? If yes, we have to standardize the single time series, before building the final arrays, or should we standardize the final array, so the lined up time series?