R Programming Language Certification Research & Evidence-Based Practice 5

Question 1

Which R approach is used to implement k-fold cross-validation for evaluating predictive model performance?

Accepted Answer

Using the caret or tidymodels package with trainControl(method='cv', number=k)

Answer

The caret package's trainControl(method='cv', number=k) sets up k-fold cross-validation for unbiased model evaluation.

Question 2

A researcher uses `mice` package in R. What research problem does this address?

Accepted Answer

Missing data imputation using chained equations

Answer

The mice package implements Multiple Imputation by Chained Equations (MICE) to handle missing data in research datasets.

Question 3

In R, `lavaan::sem()` is used for which type of analysis common in social science research?

Accepted Answer

Structural Equation Modeling

Answer

The lavaan package's sem() function fits Structural Equation Models, allowing simultaneous estimation of multiple relationships.

Question 4

Which R function implements the Wilcoxon rank-sum test as a non-parametric alternative to the independent-samples t-test?

Accepted Answer

wilcox.test(x, y, paired = FALSE)

Answer

wilcox.test() with paired = FALSE performs the Wilcoxon rank-sum (Mann-Whitney U) test for two independent groups.

Question 5

In evidence-based research, what does `AIC` (Akaike Information Criterion) help researchers do when comparing R models?

Accepted Answer

Select the model with the best balance of fit and complexity

Answer

AIC penalizes model complexity while rewarding fit; lower AIC indicates a better-balanced model among candidates.

R Programming Language Certification Practice Test