11.
Which evaluation metric is typically used for regression models and measures the average squared difference between predicted and actual values?

12.
In model evaluation, what is the primary disadvantage of using the training dataset to assess a model's performance?

14.
What does the term "bias" refer to in model evaluation and validation?

15.
What is the primary purpose of a confusion matrix in model evaluation?

16.
In model evaluation, what is the primary purpose of a learning curve?

17.
Which metric is used to evaluate the performance of a regression model when you want to know how close the predicted values are to the actual values?

18.
What does the term "underfitting" refer to in the context of model evaluation and validation?

19.
In cross-validation, what is the main drawback of Leave-One-Out Cross-Validation (LOOCV) compared to k-fold cross-validation?

20.
What is the primary purpose of a ROC-AUC (Receiver Operating Characteristic - Area Under the Curve) score in model evaluation?