Is it a problem for linear regression (
lm in R) to have observations that have multiple values for a given factor? For example, I have the weekly average sales
Y for many products and for each product I have information about the color (
X1), technology (
X2), design (
X3). With these three categorical variables, I want to see which might be indicative of higher / lower average weekly sales (
Is it a problem if products can take on several values in a factor? For example, suppose there are 20 different colors (
X1) across all products and that product
ABC comes in three colors, 5 technologies
X2 and 2 designs
Can I handle this with OLS / linear regression using LM in R, or will I get wrong results?
Also, it is not a problem that all my predictor variables are categorical, correct?