Table 3.

Radiograph adequacy analysis according to patient age. Chi-squared statistic was ascertained against the null hypothesis that there is no difference in adequacy rates between different age categories

Age (years)	Radiograph	adequacy		Total in age group (n)	Proportion of patients	Suboptimal scans
	Optimal	Suboptimal				Expected (n)	Observed (n)	Discrepancy between O and E
	(n)	(n)	(%)
1–10	90	30	25	120	0.08	61.82	30	16.38
11–20	43	23	34.85	66	0.04	34	23	3.56
21–30	28	23	45.1	51	0.03	26.27	23	0.41
31–40	28	19	40.43	47	0.03	24.21	19	1.12
41–50	79	44	35.77	123	0.08	63.37	44	5.92
51–60	98	90	47.87	188	0.12	96.85	90	0.48
61–70	113	147	56.54	260	0.17	133.94	147	1.27
71–80	139	191	57.88	330	0.22	170.01	191	2.59
81–90	98	166	62.88	264	0.17	136.01	166	6.62
91+	19	48	71.64	67	0.04	34.52	48	5.27
Total	735	781	47.8	1,516	1	781	781	43.62a

^aχ² statistic, 9 degrees of freedom, P < 0.001 (null hypothesis rejected). E, expected; O, observed.