[R-sig-eco] Function predict

[Manuel Spínola]

Dear list members,

I am fitting a logistic regression with 5 explanatory factors (which I 
converted to factors):

mod6 = glm(condicion ~ iluminacion + animales + cielo.raso + piso + 
paredes, family=binomial, data=reglog)

I want to obtain the predicted probabilities and the se using the 
function "predict" for some combination of the factors.

iluminacion = 1
animales = 0
cielo.raso = 0
piso = 0
paredes = 0

newdata1 = data.frame(iluminacion, animales, cielo.raso, piso, paredes)

newdata1$cond = predict(mod6, newdata = newdata1, type="response")

 > newdata1$cond = predict(mod6, newdata = newdata1, type="response")
Aviso en model.frame.default(Terms, newdata, na.action = na.action, xlev 
= object$xlevels) :
  variable 'iluminacion' is not a factor
Aviso en model.frame.default(Terms, newdata, na.action = na.action, xlev 
= object$xlevels) :
  variable 'animales' is not a factor
Aviso en model.frame.default(Terms, newdata, na.action = na.action, xlev 
= object$xlevels) :
  variable 'cielo.raso' is not a factor
Aviso en model.frame.default(Terms, newdata, na.action = na.action, xlev 
= object$xlevels) :
  variable 'piso' is not a factor
Aviso en model.frame.default(Terms, newdata, na.action = na.action, xlev 
= object$xlevels) :
  variable 'paredes' is not a factor
Error: variables 'iluminacion', 'animales', 'cielo.raso', 'piso', 
'paredes' were specified with different types from the fit

I don't understand what is wrong.
Any help will be appreciated.

Best,

Manuel

-- 
Manuel Spínola, Ph.D.
Instituto Internacional en Conservación y Manejo de Vida Silvestre
Universidad Nacional
Apartado 1350-3000
Heredia
COSTA RICA
mspinola at una.ac.cr
mspinola10 at gmail.com
Teléfono: (506) 2277-3598
Fax: (506) 2237-7036