Table 5.

Summary statistics of the difference and the absolute value of the difference between the estimated age and the chronological age in the balanced sample

Panel A: age estimation error,  E
Variable		n (%)	Demirjian mean (s.d.)	Willems mean (s.d.)	p Value
Sex	Female	265 (54)	0.05 (1.63)	− 0.31 (1.65)	< 0.01
	Male	228 (46)	0.56 (1.57)	0.52 (1.73)	0.47
		p Value	< 0.01	< 0.01
Presence of rheumatoid arthritis	Yes	60 (12)	0.54 (1.07)	− 0.31 (1.22)	< 0.01
	No	433 (88)	0.25 (1.68)	0.13 (1.79)	< 0.01
		p Value	0.07	0.02
Panel B: absolute age estimation error, |E|
Variable			Demirjian median (1st–3rd quartile)	Willems median (1st–3rd quartile)	p Value
Sex	Female		0.97 (0.48–1.80)	1.13 (0.50–1.88)	0.10
	Male		1.05 (0.47–1.93)	1.03 (0.53–1.96)	0.03
		p Value	0.68	0.64
Presence of rheumatoid arthritis	Yes		0.68 (0.26–1.05)	0.71 (0.48–1.39)	0.40
	No		1.08 (0.50–1.92)	1.14 (0.52–2.02)	< 0.01
		p Value	< 0.01	0.01

The p value refers to the significance of a t statistics in panel A and to a significance of Wilcoxon statistics in Panel B