R Programming Language Certification Statistical Analysis & Modeling 2

Question 1

Which family argument in glm() is used for logistic regression?

Accepted Answer

binomial

Answer

Logistic regression models binary outcomes using glm() with family=binomial, which applies the logit link function by default.

Question 2

What does the confint() function compute for a fitted model in R?

Accepted Answer

Confidence intervals for model coefficients

Answer

confint() returns confidence intervals for the parameters of a fitted model, defaulting to 95% confidence level.

Question 3

Which test should you use to compare variances between two groups in R?

Accepted Answer

var.test()

Answer

var.test() performs an F-test to compare the variances of two groups and determines if they are statistically equal.

Question 4

What does AIC stand for in model selection?

Accepted Answer

Akaike Information Criterion

Answer

AIC (Akaike Information Criterion) penalizes model complexity to balance goodness of fit with parsimony; lower AIC indicates a better model.

Question 5

Which R function performs a Wilcoxon rank-sum test (non-parametric equivalent of t-test)?

Accepted Answer

wilcox.test()

Answer

wilcox.test() performs both the Wilcoxon signed-rank test (one-sample/paired) and the Wilcoxon rank-sum (Mann-Whitney) test for two independent samples.

R Programming Language Certification Practice Test

R Programming Language Certification Practice Test

R Programming Language Certification Statistical Analysis & Modeling 2