When I fit a linear model in R with categorical variables of X (I have 3 levels). As R works it does not include one of these levels in the model output to avoid overfitting the model. But I need to know one of these levels estimated values how can I do this?

  • $\begingroup$ It would be helpful to show us your output. This isn't really a question about R, it's a question about baseline or reference levels and how to interpret the regression output - which is on-topic here. I suspected this to be a duplicate of an existing question ... but if it is I can't find it. This question ought to illustrate the general idea when there are two categorical variables, or this question is closer to a duplicate but doesn't show a regression output. $\endgroup$ – Silverfish Oct 29 '15 at 22:30
  • $\begingroup$ You can calculate them easily once you understand reference level coding or you can fit the model with level means coding. See the linked thread. $\endgroup$ – gung - Reinstate Monica Oct 29 '15 at 22:52

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