tests/testthat/test-influence.R

In olsrr: Tools for Building OLS Regression Models

context("influence")

model <- lm(mpg ~ disp + hp + wt + drat + qsec, data = mtcars)

test_that("leverage matches hat from influence.measures", {
  s1 <- round(ols_leverage(model), 4)
  s2 <- unname(round(influence.measures(model)[[1]][, 10], 4))
  expect_equal(s1, s2)
})


test_that("hadi measure matches the textbook example", {
  model <- lm(Nitrogen ~ ComIndl, data = rivers)
  act <- unname(round(ols_hadi(model)$hadi, 2))
  exp <- c(
    0.06, 0.07, 0.58, 0.77, 2.04, 0.10, 0.60, 0.37, 0.07, 0.08,
    0.13, 0.14, 0.15, 0.13, 0.16, 0.09, 0.12, 0.09, 0.19, 0.11
  )
  expect_equal(act, exp)
})

test_that("predicted rsquared output matches the expected result", {
  model <- lm(y ~ x4, data = cement)
  act <- round(ols_pred_rsq(model), 3)
  expect_equal(act, 0.56)

  model <- lm(y ~ x2, data = cement)
  act <- round(ols_pred_rsq(model), 3)
  expect_equal(act, 0.557)

  model <- lm(y ~ x1 + x2, data = cement)
  act <- round(ols_pred_rsq(model), 3)
  expect_equal(act, 0.965)

  model <- lm(y ~ x1 + x4, data = cement)
  act <- round(ols_pred_rsq(model), 3)
  expect_equal(act, 0.955)

  model <- lm(y ~ x1 + x2 + x4, data = cement)
  act <- round(ols_pred_rsq(model), 3)
  expect_equal(act, 0.969)

  model <- lm(y ~ x1 + x2 + x3, data = cement)
  act <- round(ols_pred_rsq(model), 3)
  expect_equal(act, 0.967)

  model <- lm(y ~ x1 + x2 + x3 + x4, data = cement)
  act <- round(ols_pred_rsq(model), 3)
  expect_equal(act, 0.959)
})


test_that("output from ols_test_outlier is as expected", {

  model <- lm(y ~ ., data = stepdata)
  act   <- ols_test_outlier(model)
  expect_equal(round(act$studentized_residual, 2), 4.33)
  expect_equal(round(act$unadjusted_p_val, 2), 0)
  expect_equal(round(act$bonferroni_p_val, 2), 0.3)
})