9. A confusion matrix is a classification tool used to evaluate which of the following (select all that apply)?

a. True Positive Rates (Sensitivity)

b. True Negative Rates (Specificity)

c. False Positive Rates

d. False Negative Rates

e.Overall Accuracy Rates

f. A and B Only

10. Which of the following are true statements regarding k-fold cross-validation (select all that apply)?

a. k-fold CV involves randomly separating observations into groups (or folds).

b. k represents the number of groups into which the observations are partitioned.

c. k-1 folds are used for model training; the remaining fold is used to evaluate model performance.

d. k is generally set to the number of observations in the dataset.

e. k-fold CV is a more rigorous method of evaluating model performance as compared with the validation set approach.