Pearson's Chi-squared Test


Import packages

library(stats)


Prepare data

mtcars_data <- mtcars
mtcars_data$am <- as.factor(mtcars_data$am) # converting predictors to factor 
mtcars_data$cyl <- as.factor(mtcars_data$cyl)


Student's t-test, assessing difference in means for two groups

chisq.test(table(mtcars_data$am, mtcars_data$cyl)) # Assess Transmission differences by number of cylinders

## Warning in chisq …
more ...

Student's t-Test


Prepare data

mtcars_data <- mtcars
mtcars_data$am <- as.factor(mtcars_data$am)


Student's t-test, assessing difference in means for two groups

t.test(mpg ~ am, data = mtcars_data) # Assess mpg differences by transmission status (automatic vs. manual)

## 
##  Welch Two Sample t-test
## 
## data:  mpg by am
## t = -3.7671, df = 18.332, p-value = 0 …
more ...

Wilcoxon Rank Sum Test


Import packages

library(datasets)
library(stats)


Prepare data

mtcars_data <- datasets::mtcars
mtcars_data$am <- as.factor(mtcars_data$am)


Wilcoxon Rank Sum Test, non-parametric equivalent to t-test (assess population mean difference in two groups)

wilcox.test(cyl ~ am, data = mtcars_data) # Assess mpg differences by transmission status (automatic vs. manual)

## 
##  Wilcoxon rank sum …
more ...