Table 3

Variable	Groups	x² statistic^a (df)	p-value
Failure mode	A vs. B	7.792(1)	0.007*
	A vs. C	8.533(1)	0.003*
	A vs. D	7.385(1)	0.007*
	B vs. C	25.836(1)	<0.001*
	B vs. D	Constant	Constant
	C vs. D	24.889(1)	<0.001*

^aChi-square test for independence
*Significant difference

Table 3: Comparison of failure mode between each pair of study groups.