
 # attach both packages and load the data set


 # obtain an overview over the data set


 # estimate the simple regression model


 # print the summary to the console


# attach both packages and load the data set
library(AER)
library(MASS)
data("Boston")
# obtain an overview over the data set
summary(Boston)
# or
str(Boston)
# or
head(Boston)
# estimate the simple regression model
bh_mod <- lm(medv ~ lstat, data = Boston)
# print the summary to the console
coeftest(bh_mod, vcov. = vcovHC)


test_function("library", index = 1)
test_function("library", index = 2)
test_function("data")

test_or({
test_function("head")
},{
test_function("summary")
},{
test_function("str")
})

test_function("coeftest", args=c("x", "vcov."), eval = F)

test_or({
  test_object("bh_mod")
},{
  f <- ex() %>% override_solution("lm(Boston$medv ~ Boston$lstat)") %>% check_function("lm")
  f %>% check_arg("formula") %>% check_equal()
},{
  f <- ex() %>% override_solution("attach(Boston);lm(medv ~ lstat)") %>% check_function("lm")
  f %>% check_arg("formula") %>% check_equal()
})

success_msg("Correct. Notice that both coefficients are highly significant.")