Table 10: Statistical tests of hypotheses of : Both Wilcoxon signed rank sum test and one sample -test indicate the error to be very likely nonzero. For adjusted model, the variability of can be explained by randomness.

Wilcoxon test One sample -test
value df value

Original 166 0.0004871 5.042 18 0.00008486
Adjusted 61 0.1776 18 0.1866