Table 4.

Summary statistics of the used data sets.

Variable	Minimum	Mean	Median	Maximum	Variance	Skewness	Kurtosis	n
y	0.6060	0.8375	0.8520	0.9660	0.0101	−0.5054	2.2943	37
$x_1$	423.3000	490.2000	498.0000	526.7000	695.3056	−1.0763	3.7353	37
$x_2$	0.4930	0.8546	0.9020	0.9320	0.0095	−2.0060	7.1513	37
$x_3$	0.0590	0.2394	0.2310	0.4530	0.0079	0.1641	2.5454	37