A study of the provision of hospital based dental general anaesthetic services for children in the northwest of England: part 1 - a comparison of service delivery between six hospitals

Table 4 One sample T test for IMD - study (study) mean and population (pop) mean

	Study sample IMD			95% CI		Pop IMD	One sample T test
Area	N	Mean	s.d.	Lower	Upper	Mean
1	115	45.776	19.330	42.205	49.347	43.56	t(114) = 2.578, p = 0.011, dif 4.46 95%CI 1.075-8.217
2	46	36.831	17.680	31.581	42.082	31.08	t(45) = 2.645, p = 0.011, dif 6.880 95%CI 1.645-12.116
3	30	28.129	16.648	21.912	34.346	17.05	t(29) = 3.645, p = 0.001, dif 11.079 95%CI 4.862-17.296*
4	73	47.696	19.388	43.173	52.220	41.01	t(73) = 3.117, p = 0.003, dif 7.091 95%CI 2.558-11.624*
(5 & 6)	163	44.647	21.385	41.339	47.954	43.45	t(162) = 0.714, p = 0.476, dif 1.19663 95%CI -2.110-4.504

*Significantly different following Bonferroni correction p < 0.008. Area 5 and 6 combined as they served the same population.
A t test was carried out given the only available data for area IMD was the mean IMD score meaning a t-test was the most appropriate statistical test to use. Area IMD score was based on information gained from PCO/PCT data from Public Health England, 2010 information (http://www.apho.org.uk/resource/item.aspx?RID=110540).

ISSN: 1472-6831