Explained Variance Score
"X explains p% of the variance in Y" means that when we know X, the remaining variance of Y becomes (1-p) times the total variance
A metric that indicates how well a model explains the variance (variability) in the data
- 1.0: Model perfectly explains all variance
- 0.0: Model explains nothing (equivalent to always predicting the mean)
- Negative: Model makes variance worse (predictions are worse than mean)
