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logistic regression
2 messages · Darin Brooks, Kevin E. Thorpe
Darin Brooks wrote:
Good afternoon I have what I hope is a simple logistic regression issue. I started with 44 independent variables and then used the drop1, test="chisq" to reduce the list to 8 significant independent variables. drop1(sep22lr, test="Chisq") and wound up with this model: Model: MIN_Mstocked ~ ORG_CODE + BECLBL08 + PEM_SScat + SOIL_NUTR + cSEEDSRCE_SW + cMSP + ceFFP + cEXT_Cold 4 of the remaining variables are categorical and 4 are continuous. However, when I run a glm and then a summary on the glm - some of the categorical data is missing from the output. The PEM_SScat is missing only one variable ... the BECLBL08 is missing several variables ... the ORG_CODE is missing 4 .. and the SOIL_NUTR is missing 1 variable. It seems arbitrary to the number of variables missing. Is there something wrong with my syntax in calling the logistic model? Am I not understanding the inputs correctly? Any help would be appreciated.
I'm not sure I fully understand your question. It sounds like you created your own dummy variables for your categorical variables. Did you? Or did you use factor variables for your categorical variables? If the latter, then I REALLY don't understand your question. Kevin
Kevin E. Thorpe Biostatistician/Trialist, Knowledge Translation Program Assistant Professor, Dalla Lana School of Public Health University of Toronto email: kevin.thorpe at utoronto.ca Tel: 416.864.5776 Fax: 416.864.6057