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) mod_ni <- lm(ts ~ cs - 1) # plot the regression lines of both models plot(cs, ts) # plot the regression lines of both models plot(cs, ts) abline(mod, col = "blue") abline(mod_ni, col = "red") test_predefined_objects("mod") test_predefined_objects("mod_ni") test_function("abline", index=1) test_function("abline", index=2) success_msg("Yep, that looks good!")