R Programming Language Certification Statistical Analysis & Modeling in R 3

Question 1

What does AIC stand for and what is it used for in R model selection?

Accepted Answer

Akaike Information Criterion; compares model fit while penalizing for complexity

Answer

Adjusted Intercept Coefficient; adjusts regression estimates

Answer

Average Interval Coverage; estimates confidence width

Answer

Algorithmic Information Criterion; measures data compression

Question 2

Which R function computes the variance of a numeric vector?

Accepted Answer

var()

Answer

variance()

Answer

sd()^2 only

Answer

cov()

Question 3

What is the default method used by cor() in R for computing correlation?

Accepted Answer

Pearson

Answer

Spearman

Answer

Kendall

Answer

Point-biserial

Question 4

Which function in R is used to perform a Wilcoxon rank-sum test (non-parametric alternative to t-test)?

Accepted Answer

wilcox.test()

Answer

kruskal.test()

Answer

rank.test()

Answer

nonpar.test()

Question 5

In R, what does the residuals() function return for a linear model?

Accepted Answer

The difference between observed and fitted values

Answer

The model coefficients

Answer

The standard errors

Answer

The leverage values

Question 6

Which R package is the primary toolkit for survival analysis and time-to-event data?

Accepted Answer

survival

Answer

survminer

Answer

timereg

Answer

eventanalysis