tests/testthat/test-step-backward-output.R
In cmlopera/olsrr: Tools for Building OLS Regression Models
context("stepwise backward regression output")
model <- lm(y ~ ., data = surgical)
test_that("output from stepwise backward regression is as expected", {
x <- cat("Backward Elimination Method
Candidate Terms:
1 . bcs
2 . pindex
3 . enzyme_test
4 . liver_test
5 . age
6 . gender
7 . alc_mod
8 . alc_heavy
--------------------------------------------------------------------------
Elimination Summary
--------------------------------------------------------------------------
Variable Adj.
Step Removed R-Square R-Square C(p) AIC RMSE
--------------------------------------------------------------------------
1 alc_mod 0.7818 0.7486 7.0141 734.4068 199.2637
2 gender 0.7814 0.7535 5.0870 732.4942 197.2921
3 age 0.7809 0.7581 3.1925 730.6204 195.4544
--------------------------------------------------------------------------")
expect_output(print(ols_step_backward_p(model)), x)
})
test_that("output from stepwise backward regression is as expected when details == TRUE", {
x <- cat("Backward Elimination: Step 1
Variable alc_mod Removed
Model Summary
-----------------------------------------------------------------
R 0.884 RMSE 199.264
R-Squared 0.782 Coef. Var 28.381
Adj. R-Squared 0.749 MSE 39706.040
Pred R-Squared 0.678 MAE 137.053
-----------------------------------------------------------------
RMSE: Root Mean Square Error
MSE: Mean Square Error
MAE: Mean Absolute Error
ANOVA
-----------------------------------------------------------------------
Sum of
Squares DF Mean Square F Sig.
-----------------------------------------------------------------------
Regression 6543042.709 7 934720.387 23.541 0.0000
Residual 1826477.828 46 39706.040
Total 8369520.537 53
-----------------------------------------------------------------------
Parameter Estimates
------------------------------------------------------------------------------------------------
model Beta Std. Error Std. Beta t Sig lower upper
------------------------------------------------------------------------------------------------
(Intercept) -1145.971 238.536 -4.804 0.000 -1626.119 -665.822
bcs 62.274 24.187 0.251 2.575 0.013 13.589 110.959
pindex 8.987 1.850 0.382 4.857 0.000 5.262 12.711
enzyme_test 9.875 1.720 0.528 5.743 0.000 6.414 13.337
liver_test 50.763 44.379 0.137 1.144 0.259 -38.567 140.093
age -0.911 2.599 -0.025 -0.351 0.728 -6.142 4.320
gender 15.786 57.840 0.020 0.273 0.786 -100.639 132.212
alc_heavy 315.854 73.849 0.312 4.277 0.000 167.202 464.505
------------------------------------------------------------------------------------------------
Backward Elimination: Step 2
Variable gender Removed
Model Summary
-----------------------------------------------------------------
R 0.884 RMSE 197.292
R-Squared 0.781 Coef. Var 28.101
Adj. R-Squared 0.754 MSE 38924.162
Pred R-Squared 0.692 MAE 138.160
-----------------------------------------------------------------
RMSE: Root Mean Square Error
MSE: Mean Square Error
MAE: Mean Absolute Error
ANOVA
-----------------------------------------------------------------------
Sum of
Squares DF Mean Square F Sig.
-----------------------------------------------------------------------
Regression 6540084.920 6 1090014.153 28.004 0.0000
Residual 1829435.617 47 38924.162
Total 8369520.537 53
-----------------------------------------------------------------------
Parameter Estimates
------------------------------------------------------------------------------------------------
model Beta Std. Error Std. Beta t Sig lower upper
------------------------------------------------------------------------------------------------
(Intercept) -1143.080 235.943 -4.845 0.000 -1617.737 -668.424
bcs 61.424 23.748 0.248 2.586 0.013 13.649 109.199
pindex 8.974 1.832 0.382 4.900 0.000 5.290 12.659
enzyme_test 9.852 1.700 0.527 5.794 0.000 6.431 13.273
liver_test 54.053 42.288 0.146 1.278 0.207 -31.019 139.125
age -0.850 2.563 -0.024 -0.332 0.742 -6.007 4.307
alc_heavy 314.585 72.974 0.310 4.311 0.000 167.781 461.390
------------------------------------------------------------------------------------------------
Backward Elimination: Step 3
Variable age Removed
Model Summary
-----------------------------------------------------------------
R 0.884 RMSE 195.454
R-Squared 0.781 Coef. Var 27.839
Adj. R-Squared 0.758 MSE 38202.426
Pred R-Squared 0.700 MAE 137.656
-----------------------------------------------------------------
RMSE: Root Mean Square Error
MSE: Mean Square Error
MAE: Mean Absolute Error
ANOVA
-----------------------------------------------------------------------
Sum of
Squares DF Mean Square F Sig.
-----------------------------------------------------------------------
Regression 6535804.090 5 1307160.818 34.217 0.0000
Residual 1833716.447 48 38202.426
Total 8369520.537 53
-----------------------------------------------------------------------
Parameter Estimates
------------------------------------------------------------------------------------------------
model Beta Std. Error Std. Beta t Sig lower upper
------------------------------------------------------------------------------------------------
(Intercept) -1178.330 208.682 -5.647 0.000 -1597.914 -758.746
bcs 59.864 23.060 0.241 2.596 0.012 13.498 106.230
pindex 8.924 1.808 0.380 4.935 0.000 5.288 12.559
enzyme_test 9.748 1.656 0.521 5.887 0.000 6.419 13.077
liver_test 58.064 40.144 0.156 1.446 0.155 -22.652 138.779
alc_heavy 317.848 71.634 0.314 4.437 0.000 173.818 461.878
------------------------------------------------------------------------------------------------
No more variables satisfy the condition of prem: 0.3
Backward Elimination Method
Candidate Terms:
1 . bcs
2 . pindex
3 . enzyme_test
4 . liver_test
5 . age
6 . gender
7 . alc_mod
8 . alc_heavy
--------------------------------------------------------------------------
Elimination Summary
--------------------------------------------------------------------------
Variable Adj.
Step Removed R-Square R-Square C(p) AIC RMSE
--------------------------------------------------------------------------
1 alc_mod 0.7818 0.7486 7.0141 734.4068 199.2637
2 gender 0.7814 0.7535 5.0870 732.4942 197.2921
3 age 0.7809 0.7581 3.1925 730.6204 195.4544
--------------------------------------------------------------------------")
expect_output(print(ols_step_backward_p(model, details = TRUE)), x)
})
cmlopera/olsrr documentation built on May 26, 2019, 10:34 a.m.
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context("stepwise backward regression output")
model <- lm(y ~ ., data = surgical)
test_that("output from stepwise backward regression is as expected", {
x <- cat("Backward Elimination Method
Candidate Terms:
1 . bcs
2 . pindex
3 . enzyme_test
4 . liver_test
5 . age
6 . gender
7 . alc_mod
8 . alc_heavy
--------------------------------------------------------------------------
Elimination Summary
--------------------------------------------------------------------------
Variable Adj.
Step Removed R-Square R-Square C(p) AIC RMSE
--------------------------------------------------------------------------
1 alc_mod 0.7818 0.7486 7.0141 734.4068 199.2637
2 gender 0.7814 0.7535 5.0870 732.4942 197.2921
3 age 0.7809 0.7581 3.1925 730.6204 195.4544
--------------------------------------------------------------------------")
expect_output(print(ols_step_backward_p(model)), x)
})
test_that("output from stepwise backward regression is as expected when details == TRUE", {
x <- cat("Backward Elimination: Step 1
Variable alc_mod Removed
Model Summary
-----------------------------------------------------------------
R 0.884 RMSE 199.264
R-Squared 0.782 Coef. Var 28.381
Adj. R-Squared 0.749 MSE 39706.040
Pred R-Squared 0.678 MAE 137.053
-----------------------------------------------------------------
RMSE: Root Mean Square Error
MSE: Mean Square Error
MAE: Mean Absolute Error
ANOVA
-----------------------------------------------------------------------
Sum of
Squares DF Mean Square F Sig.
-----------------------------------------------------------------------
Regression 6543042.709 7 934720.387 23.541 0.0000
Residual 1826477.828 46 39706.040
Total 8369520.537 53
-----------------------------------------------------------------------
Parameter Estimates
------------------------------------------------------------------------------------------------
model Beta Std. Error Std. Beta t Sig lower upper
------------------------------------------------------------------------------------------------
(Intercept) -1145.971 238.536 -4.804 0.000 -1626.119 -665.822
bcs 62.274 24.187 0.251 2.575 0.013 13.589 110.959
pindex 8.987 1.850 0.382 4.857 0.000 5.262 12.711
enzyme_test 9.875 1.720 0.528 5.743 0.000 6.414 13.337
liver_test 50.763 44.379 0.137 1.144 0.259 -38.567 140.093
age -0.911 2.599 -0.025 -0.351 0.728 -6.142 4.320
gender 15.786 57.840 0.020 0.273 0.786 -100.639 132.212
alc_heavy 315.854 73.849 0.312 4.277 0.000 167.202 464.505
------------------------------------------------------------------------------------------------
Backward Elimination: Step 2
Variable gender Removed
Model Summary
-----------------------------------------------------------------
R 0.884 RMSE 197.292
R-Squared 0.781 Coef. Var 28.101
Adj. R-Squared 0.754 MSE 38924.162
Pred R-Squared 0.692 MAE 138.160
-----------------------------------------------------------------
RMSE: Root Mean Square Error
MSE: Mean Square Error
MAE: Mean Absolute Error
ANOVA
-----------------------------------------------------------------------
Sum of
Squares DF Mean Square F Sig.
-----------------------------------------------------------------------
Regression 6540084.920 6 1090014.153 28.004 0.0000
Residual 1829435.617 47 38924.162
Total 8369520.537 53
-----------------------------------------------------------------------
Parameter Estimates
------------------------------------------------------------------------------------------------
model Beta Std. Error Std. Beta t Sig lower upper
------------------------------------------------------------------------------------------------
(Intercept) -1143.080 235.943 -4.845 0.000 -1617.737 -668.424
bcs 61.424 23.748 0.248 2.586 0.013 13.649 109.199
pindex 8.974 1.832 0.382 4.900 0.000 5.290 12.659
enzyme_test 9.852 1.700 0.527 5.794 0.000 6.431 13.273
liver_test 54.053 42.288 0.146 1.278 0.207 -31.019 139.125
age -0.850 2.563 -0.024 -0.332 0.742 -6.007 4.307
alc_heavy 314.585 72.974 0.310 4.311 0.000 167.781 461.390
------------------------------------------------------------------------------------------------
Backward Elimination: Step 3
Variable age Removed
Model Summary
-----------------------------------------------------------------
R 0.884 RMSE 195.454
R-Squared 0.781 Coef. Var 27.839
Adj. R-Squared 0.758 MSE 38202.426
Pred R-Squared 0.700 MAE 137.656
-----------------------------------------------------------------
RMSE: Root Mean Square Error
MSE: Mean Square Error
MAE: Mean Absolute Error
ANOVA
-----------------------------------------------------------------------
Sum of
Squares DF Mean Square F Sig.
-----------------------------------------------------------------------
Regression 6535804.090 5 1307160.818 34.217 0.0000
Residual 1833716.447 48 38202.426
Total 8369520.537 53
-----------------------------------------------------------------------
Parameter Estimates
------------------------------------------------------------------------------------------------
model Beta Std. Error Std. Beta t Sig lower upper
------------------------------------------------------------------------------------------------
(Intercept) -1178.330 208.682 -5.647 0.000 -1597.914 -758.746
bcs 59.864 23.060 0.241 2.596 0.012 13.498 106.230
pindex 8.924 1.808 0.380 4.935 0.000 5.288 12.559
enzyme_test 9.748 1.656 0.521 5.887 0.000 6.419 13.077
liver_test 58.064 40.144 0.156 1.446 0.155 -22.652 138.779
alc_heavy 317.848 71.634 0.314 4.437 0.000 173.818 461.878
------------------------------------------------------------------------------------------------
No more variables satisfy the condition of prem: 0.3
Backward Elimination Method
Candidate Terms:
1 . bcs
2 . pindex
3 . enzyme_test
4 . liver_test
5 . age
6 . gender
7 . alc_mod
8 . alc_heavy
--------------------------------------------------------------------------
Elimination Summary
--------------------------------------------------------------------------
Variable Adj.
Step Removed R-Square R-Square C(p) AIC RMSE
--------------------------------------------------------------------------
1 alc_mod 0.7818 0.7486 7.0141 734.4068 199.2637
2 gender 0.7814 0.7535 5.0870 732.4942 197.2921
3 age 0.7809 0.7581 3.1925 730.6204 195.4544
--------------------------------------------------------------------------")
expect_output(print(ols_step_backward_p(model, details = TRUE)), x)
})
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