R Programming Language Certification Research & Evidence-Based Practice 4

Question 1

In R, which package is specifically designed for conducting meta-analyses, providing functions like `rma()`?

Accepted Answer

metafor

Answer

The metafor package provides comprehensive meta-analysis tools including the rma() function for random/fixed-effects models.

Question 2

A researcher uses `sample(x, size = n, replace = FALSE)` in R. What is this technique called when used to create bootstrap confidence intervals?

Accepted Answer

Bootstrap resampling

Answer

Bootstrap resampling draws repeated samples with replacement (replace = TRUE) to estimate sampling distributions.

Question 3

Which R function from the `pwr` package calculates the sample size needed to achieve a target statistical power?

Accepted Answer

pwr.t.test() from pwr package

Answer

pwr.t.test() from the pwr package computes power or required n for t-tests given effect size, alpha, and power.

Question 4

In R, what does `summary(lm_model)$r.squared` return?

Accepted Answer

The proportion of variance in the outcome explained by the model

Answer

R-squared represents the proportion of total variance in the dependent variable explained by the linear model.

Question 5

A researcher applies `Bonferroni` correction in R using `p.adjust(p_values, method = 'bonferroni')`. What problem does this address?

Accepted Answer

Inflated Type I error from multiple comparisons

Answer

Bonferroni correction controls the family-wise error rate when conducting multiple hypothesis tests simultaneously.

R Programming Language Certification Practice Test