I had a face to face interview for a data scientist job a few days ago. One of the questions I was asked was: in the case of classifier predicting the brand of TV from some features (price, size, specs, ...) out of 4 possible brands, how do you encode the brand variable? My answer was one hot encoding
, it was accepted but then they asked me to do it explicitly and I sketched something like:
brand A -> [1,0,0,0]
brand B -> [0,1,0,0]
brand C -> [0,0,1,0]
brand D -> [0,0,0,1]
And then, I was corrected under the reason that these columns were not independent. And that the solution should have been three binary columns instead.
Later it hit me that I do not know why independence is required, and also that three binary variables are not independent. Two would be.
Can someone provide some explanation to help with my confusion?
001, 010, 011, 100
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