Qm
Statistics

The same variable in two units: percent and decimal

multicollinearityperfect-collinearityols

Building a feature table, you include a stock's prior return twice by mistake: once as a decimal (ret_dec, e.g. 0.03) and once as a percentage (ret_pct, e.g. 3.0). Both go into the regression. It fails to estimate.

Why does this break OLS even though there are no dummy variables?

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Correlation Filtering and Redundant FeaturesDummy Variables and Interaction TermsThe Frisch-Waugh-Lovell TheoremThe Gauss–Markov TheoremLeverage and Influential Observations

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