library(readr) library(AER) Titanic_2 <- read_csv("https://stanford.io/2O9RUCF")[,-3] colnames(Titanic_2) = c("Survived", "Class", "Sex", "Age", "Siblings", "Parents", "Fare") # generate `t_abs`, a contingency table of `Survived` and `Class` # generate `t_rel`, the table of the relative frequencies # create the barplot # generate `t_abs`, a contingency table of `Survived` and `Class` t_abs <-table(Titanic_2$Survived, Titanic_2$Class) # generate `t_rel`, the table of the relative frequencies t_rel <- t_abs/nrow(Titanic_2) # create the barplot barplot(table(Titanic_2$Survived, Titanic_2$Class)/nrow(Titanic_2), col = c("darkred","darkgreen"), ylim = c(0,0.6), main = "Relative Frequencies of Survival", xlab = "Class") test_predefined_objects("Titanic_2") test_object("t_abs") test_object("t_rel") test_function("barplot", args = "height")