I have a dataset consisting of 339 possible independent variables and 7700 observations. I used the Amelia package (I'm programming in R) in order to visualize the missing values of my data and this is what I got.
I wish to choose for my regressions the variables that I have signaled with the brown rectangle. But since I have 339 variables the labels on the x axis are unreadable and I don't know which are those variables. I have already tried x.cex=0.1 and x.cex=0.01 but the labels become too small to read. My question is how can I identify the variables in the brown rectangle?