cs <- c(23, 19, 30, 22, 23, 29, 35, 36, 33, 25)
ts <- c(430, 430, 333, 410, 390, 377, 325, 310, 328, 375)
mod <- lm(ts ~ cs)
# check the class of `mod`
# use `is.list()` on `mod`
# check the entries of `mod` using `names()`
# use the operator `$` on `mod`
# check the class of `mod`
class(mod)
# use `is.list()` on `mod`
is.list(mod)
# check the entries of `mod` using `names()`
names(mod)
# use the operator `$` on `mod`
# example:
mod$fitted.values
test_predefined_objects("mod")
test_function("class", args="x")
test_function("is.list", args="x")
test_function("names", args="x")
test_student_typed("mod$")