Exercise 1

library(ISLR)

data(Auto)
Auto <- na.omit(Auto)  # Remove missing values if any

# Quantitative Variables: mpg, cylinders, displacement, horsepower, weight, acceleration, year
# Qualitative Variables: origin, name
quantitative_vars <- c("mpg", "cylinders", "displacement", "horsepower", "weight", "acceleration", "year")
qualitative_vars <- c("origin", "name")

cat("Quantitative Variables:", paste(quantitative_vars, collapse = ", "), "\n")

## Quantitative Variables: mpg, cylinders, displacement, horsepower, weight, acceleration, year

cat("Qualitative Variables:", paste(qualitative_vars, collapse = ", "))

## Qualitative Variables: origin, name

sapply(Auto[quantitative_vars], range, na.rm = TRUE)

##       mpg cylinders displacement horsepower weight acceleration year
## [1,]  9.0         3           68         46   1613          8.0   70
## [2,] 46.6         8          455        230   5140         24.8   82

sapply(Auto[quantitative_vars], function(x) c(Mean = mean(x, na.rm = TRUE), SD = sd(x, na.rm = TRUE)))

##            mpg cylinders displacement horsepower    weight acceleration
## Mean 23.445918  5.471939      194.412  104.46939 2977.5842    15.541327
## SD    7.805007  1.705783      104.644   38.49116  849.4026     2.758864
##           year
## Mean 75.979592
## SD    3.683737

Auto_new <- Auto[-(10:85), ]

sapply(Auto_new[quantitative_vars], range, na.rm = TRUE)

##       mpg cylinders displacement horsepower weight acceleration year
## [1,] 11.0         3           68         46   1649          8.5   70
## [2,] 46.6         8          455        230   4997         24.8   82

sapply(Auto_new[quantitative_vars], function(x) c(Mean = mean(x, na.rm = TRUE), SD = sd(x, na.rm = TRUE)))

##            mpg cylinders displacement horsepower    weight acceleration
## Mean 24.404430  5.373418    187.24051  100.72152 2935.9715    15.726899
## SD    7.867283  1.654179     99.67837   35.70885  811.3002     2.693721
##           year
## Mean 77.145570
## SD    3.106217

pairs(Auto[quantitative_vars])

par(mfrow = c(2, 2))
plot(Auto$horsepower, Auto$mpg, main = "MPG vs Horsepower", xlab = "Horsepower", ylab = "MPG", col = "blue")
plot(Auto$weight, Auto$mpg, main = "MPG vs Weight", xlab = "Weight", ylab = "MPG", col = "red")
plot(Auto$displacement, Auto$mpg, main = "MPG vs Displacement", xlab = "Displacement", ylab = "MPG", col = "green")
plot(Auto$acceleration, Auto$mpg, main = "MPG vs Acceleration", xlab = "Acceleration", ylab = "MPG", col = "purple")