pub trait MeanSquaredError {
type Output;
// Required method
fn mse(&self) -> Self::Output;
}Expand description
The MeanSquaredError (MSE) is the average of the squared differences between the
($\hat{y_{i}}$) and actual values ($y_{i}$):
$$ Err = \frac{1}{n} \sum_{i=1}^{n} (y_i - \hat{y}_i)^2 $$