Threshold variable

Core explanatory variable

Strength of threshold

Coefficient of estimate

standard deviation

t-value

p-value

EI4

EI2

EI4 < 0.766

−0.028

0.014

−2.06

0.039

0.766 < EI4 < 1.019

−0.007

0.014

−0.48

0.634

EI4 > 1.019

0.043

0.018

2.45

0.015

EI6

EI4 < 0.766

0.008

0.023

0.35

0.727

0.766 < EI4 < 1.019

0.041

0.022

1.89

0.058

EI4 > 1.019

0.130

0.028

4.58

0.000