Table 6.

Numerical summary of the environmental parameters (median and mean ± standard error), and the coefficient values, t-values, and p-values of the multiple linear regression.

Parameter	Mean ± SE 1	Median	Coef 2	T-Value	p-Value
Working hours/day	6.23 ± 0.19	6.0	−0.32	−2.75	0.016 *
Number of donkeys	8.95 ± 0.60	7.5	0.22	4.20	0.001 **
Distance	54.70 ± 3.53	53.5	−0.02	−2.40	0.031 *
Concrete amount/donkey	2.52 ± 0.20	2.15	0.48	4.85	0.000 **

¹ SE = standard error of the mean, * means significant at the 5% significance level, and ** means significant at the 1% significance level, ² Coef = coefficient value