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Table 1 Stepwise variable selection on dataset A

From: Predicting emergency department visits in a large teaching hospital

Variable Estimate Standard error t-value P-value Significance level
(Intercept) 248.7786337 45.4299646 5.476 5.67e−08 <.001
Monday 11.5596282 1.0533831 10.974 <2e−16 <.001
Friday 8.4939099 1.1411012 7.444 2.32e−13 <.001
Saturday − 8.3012065 1.1525279 − 7.203 1.26e−12 <.001
Sunday − 10.3104139 2.0117598 -5.125 3.65e−07 <.001
January 2.3137231 1.4929930 1.550 0.121566 N.S.
May − 3.2596707 1.4369325 − 2.268 0.023540 <.05
August − 3.3159900 1.3688478 − 2.422 0.015616 <.05
Friday * Spring 6.7473582 2.2399643 3.012 0.002667 <0.01
Sunday * Summer 3.4651415 2.0302316 1.707 0.088216 N.S.
Tuesday * Fall − 4.7872202 1.7387084 − 2.753 0.006020 <0.01
Thursday * Fall − 4.4414934 1.7371769 − 2.557 0.010732 <.05
Saturday * Winter − 5.2470915 2.2009207 − 2.384 0.017334 <.05
Summer vacation week 1 + 2 − 8.0769673 1.7847806 − 4.525 6.85e−06 <.001
Summer vacation week 3 + 4 − 10.5916099 1.8959655 − 5.586 3.09e−08 <.001
Thursday * Summer vacation 3.5492285 2.5010552 1.419 0.156225 N.S.
Friday * Vacation − 6.5440714 2.9636941 − 2.208 0.027495 <.05
Holiday * Vacation − 5.0010994 3.2588828 − 1.535 0.125239 N.S.
Monday * Holiday − 21.0261795 3.6481167 − 5.764 1.14e−08 <.001
Thursday * Holiday − 21.0240305 5.8145506 − 3.616 0.000316 <.001
Wednesday * Holiday − 19.0692120 7.1177032 − 2.679 0.007519 <0.01
Friday * Holiday − 27.1374017 9.8894943 − 2.744 0.006191 <0.01
Carnival 10.7865927 4.1303939 2.612 0.009167 <0.01
Time trend 0.0097392 0.0013999 6.957 6.77e−12 <.001
Sunday * Time trend − 0.0053839 0.0034610 − 1.557 0.120165 N.S.
Summer vacation * Time trend − 0.0125371 0.0026263 − 4.772 2.12e−06 <.001
Maximum Temperature 0.0360680 0.0088407 4.080 4.92e−05 <.001
Winter * Mean temperature − 0.0568999 0.0255135 − 2.527 0.011666 <.05
Radiation 0.0029971 0.0009226 3.249 0.001203 <0.01
Maximum pressure − 0.0155889 0.0044522 − 3.501 0.000486 <.001
Winter * Maximum pressure 0.0007034 0.0001660 4.238 2.49e−05 <.001
Precipitation duration 0.0407058 0.0162960 2.498 0.012674 <.05
Summer * Precipitation (automatic stations) − 0.312219 0.0081872 − 3.814 0.000147 <.001
Maximum humidity − 0.1241583 0.0719627 − 1.725 0.084820 N.S.
Maximum visibility − 0.0086327 0.0042522 − 2.030 0.042636 <.05
Hours of fog 0.4447461 0.1570946 2.831 0.004744 <.01
Winter * hours of snow − 1.2095289 0.3781155 − 3.199 0.001429 <.01
Residual standard error 9.668 on 884 degrees of freedom
Multiple R-squared 0.5307
Adjusted R-squared 0.5115
F-statistic 27.76 on 36 and 884 degrees of freedom, P-value: < 2.2e−16
  1. Dataset A is based on the calendar variables plus weather predictions at the Jeroen Bosch Hospital; * = interaction; N.S. not significant