Im new in statistics. Can I use "years" as a continuos variable to see if NDVi (normalized difference vegetation index) has changed over the years positively or negatively, for example with a GLMM or GLm?
"years" equal calendar years as integers from a selected start point? If so, I don't know why this would be an issue. Though, are your data autocorrelated? Providing a sample from your dataset would be helpful even if the actual data values are made-up.
Yes, "years" as calendar years from 1984 to 2014. I don't have data yet, becacuse I want to know first if my idea is correct before collecting the data, but, for example, its the ndvi of an area through the years, the same area at the same time (summer). So my doubt was if I could use it as a continuous variable, because I read some people use it as random factor or time series, but they are other research questions.