Hello there, I was wondering if somebody could offer me some advice on which error distribution would be appropriate for the type of data I have. I'm studying what continuous predictor variables such as grooming received, rank, etc. affect the amount of grooming given. This response variable is continuous with many zeros, and so positively skewed. So I can't use gamma because of the zeros and since poisson is for count data I would probably loose lots of info when converting my data to integers. I was looking in the help archive of R and I realized that somebody had a similar problem in the past and was adviced' to use the Tweedie distribution since it was developed specifically for dealing with positive continuous data with exact zeros. I think this would be appropriate for my problem as well, but I'm not sure. I realized in the Tweedie help page that one can use a specific response distribution (Normal, Poisson, Compound Poisson, etc) by setting the variance power = to a specific number. I'm a beginner, so I really don't follow then, which response distribution to use (i.e. what variance power) that would be appropriate for continuous response data with many zeros. I hope somebody can help me with this. Thanks in advance. Cheers, Cristina.
Hello there, I was wondering if somebody could offer me some advice on which error distribution would be appropriate for the type of data I have. I'm studying what continuous predictor variables such as grooming received, rank, etc. affect the amount of grooming given. This response variable is continuous with many zeros, and so positively skewed. So I can't use gamma because of the zeros and since poisson is for count data I would probably loose lots of info when converting my data to integers. I was looking in the help archive of R and I realized that somebody had a similar problem in the past and was adviced' to use the Tweedie distribution since it was developed specifically for dealing with positive continuous data with exact zeros. I think this would be appropriate for my problem as well, but I'm not sure. I realized in the Tweedie help page that one can use a specific response distribution (Normal, Poisson, Compound Poisson, etc) by setting the variance power = to a specific number. I'm a beginner, so I really don't follow then, which response distribution to use (i.e. what variance power) that would be appropriate for continuous response data with many zeros. I hope somebody can help me with this. Thanks in advance. Cheers, Cristina.