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$fitted.values test_predefined_objects("mod") test_function("class", args="x") test_function("is.list", args="x") test_function("names", args="x") test_student_typed("mod$")