
    library(AER)
    data(CPS1985)
    dummy_mod <- lm(wage ~ gender, data = CPS1985)


  # complete the function below
  Rob_CI <- function(model) {
    SEs <- ???
    lower <- model$coef - ???
    upper <- model$coef + ???
    return(
      cbind("Lower" = lower, "Upper" = upper)
    )
  }

  # use Rob_CI() to compute the confidence intervals for both model coefficients


    # complete the function below
    Rob_CI <- function(model) {
    SEs <- sqrt(diag(vcovHC(model, type = "HC1")))
    lower <- model$coef - 1.96 * SEs
    upper <- model$coef + 1.96 * SEs
    return(
      cbind("Lower" = lower, "Upper" = upper)
    )
    }
    # use Rob_CI() to compute the confidence intervals for both model coefficients
    Rob_CI(dummy_mod)


  test_function_definition("Rob_CI",
                         function_test = test_expression_result("Rob_CI(dummy_mod)"))
  test_output_contains("Rob_CI(dummy_mod)")
  success_msg("Nice!")