[R] Strange error with log-normal models
noahsilverman at ucla.edu
Tue Apr 16 19:19:58 CEST 2013
I have some data, that when plotted looks very close to a log-normal distribution. My goal is to build a regression model to test how this variable responds to several independent variables.
To do this, I want to use the fitdistr tool from the MASS package to see how well my data fits the actual distribution, and also build a generalized linear model using the glm command.
The summary of my data is:
Min. 1st Qu. Median Mean 3rd Qu. Max.
0.0000 0.0000 0.0000 0.8617 0.8332 55.5600
So, no missing values, no negative values.
When I try to use the fitdistr command, I get an error that I don't understand:
m <- fitdistr(y, densfun="lognormal")
Error in fitdistr(y, densfun = "lognormal") : need positive values to fit a log-Normal
When I try to build a simple model, I also get an error:
l <- glm(y~ x, family=gaussian(link="log"))
Error in eval(expr, envir, enclos) : cannot find valid starting values: please specify some
Can anyone offer some suggestions?
Noah Silverman, M.S.
UCLA Department of Statistics
8117 Math Sciences Building
Los Angeles, CA 90095
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