My Y variable varies between 0 and 1 with increments of 0.067. I have a lot of zeros in my data. My questions are:
Is the residual vs. fitted plot below OK. Or as suggested in this link: Heteroscedasticity in residuals vs. fitted plot and this link: How should I interpret this residual plot? is there a floor effect? Do I need to consider a different type of model, perhaps a logistic model?
Neter et al (1989) in p247 advises 'residuals should be plotted against each independent variables.' If moderate heteroscedasticity is not an issue in residual vs. fitted plot, do I have to check for heteroscedasticity in residual vs. each individual X variable? Asking the same question differently, if my residual vs. fitted plot is fine in model Y ~ X1 + X2 + X3 + X4 + X5 (not the one in the image above), but residual vs. X4 shows heteroscedasticity, what do I do?