R Programming Language Certification Machine Learning with R 3

Question 1

What does the confusionMatrix() function from the caret package return for a classification model?

Accepted Answer

A comprehensive summary including sensitivity, specificity, PPV, and NPV

Answer

Only the overall accuracy value

Answer

Only the confusion matrix table

Answer

The model's AUC-ROC value

Question 2

Which function extracts variable importance scores from a trained caret model object?

Accepted Answer

varImp()

Answer

featureImportance()

Answer

importance()

Answer

coefPlot()

Question 3

In R, which function performs Principal Component Analysis (PCA) and is preferred for numerical stability?

Accepted Answer

prcomp()

Answer

pca()

Answer

factanal()

Answer

pcaR()

Question 4

Which R package provides the infrastructure for model stacking (ensemble of multiple trained models)?

Accepted Answer

stacks

Answer

ensemble

Answer

combineR

Answer

stackModels

Question 5

What is the main role of the 'tune' package within the tidymodels ecosystem?

Accepted Answer

Hyperparameter tuning and optimization

Answer

Preprocessing data pipelines

Answer

Model performance visualization

Answer

Loading and splitting datasets

Question 6

In tidymodels, which function combines a preprocessor (recipe) and a model specification into a single object for fitting?

Accepted Answer

workflow()

Answer

pipeline()

Answer

combine()

Answer

bundle()

Question 7

Which R package is commonly used for model-agnostic interpretability, including partial dependence plots and SHAP values?

Accepted Answer

DALEX

Answer

interpret

Answer

explainR

Answer

modelViz