Squared term
Also written: quadratic, I(ad_spend ** 2)
Adding the square of a predictor to fit a curve. Unlike a log, a squared curve eventually turns around, so use it when there really is a peak.
Also written: quadratic, I(ad_spend ** 2)
Adding the square of a predictor to fit a curve. Unlike a log, a squared curve eventually turns around, so use it when there really is a peak.