Categorical data

Practicing Statistics Interview Questions in R

Zuzanna Chmielewska

Actuary

Factors in R

x1 <- c("AB", "A", "O", "AB", "B", "B")

lvls <- c("A", "B", "AB", "O")

x2 <- factor(x1, levels = lvls)

print(x2)

[1] AB A  O  AB B  B 
Levels: A B AB O

Factors in R

x1 <- c("M", "L" , "L", "XS", "XL", "S")

lvls <- c("XS", "S", "M", "L", "XL")

x2 <- factor(x1, levels = lvls, ordered = TRUE)

print(x2)

[1] M  L  L  XS XL S 
Levels: XS < S < M < L < XL

tapply(df$value, df$level, mean)

Categorical data encoding

• label encoding
• one hot encoding
• many more!

Label encoding

Label encoding

Label encoding

Label encoding

Label encoding

One hot encoding

One hot encoding

One hot encoding

One hot encoding

One hot encoding

Summary

• types of categorical data
• factors in R
• categorical data analysis
  • table()
  • barplot()
  • tapply()
• data encoding
  • label encoding
  • one hot encoding

Let's practice!

Practicing Statistics Interview Questions in R