Table 3.

Results (equal variances assumed) of t -test for the difference of incidence rates of human Brucellosis occurrences between each subsequent and preceding year during 2006-2010

	Levene’s test		t -test for equality of means
Year	F.	Sig.	t	df	Sig.(2-tailed)	Mean difference	Std. error difference	95% lower	95% upper
2007 v.s. 2006	0.113	0.737	−0.228	176	0.820	−0.159	0.699	−1.538	1.220
2008 v.s. 2007	0.851	0.358	−1.088	176	0.278	−0.722	0.664	−2.032	0.588
2009 v.s. 2008	5.090	0.025	−2.142	176	0.034	−1.189	0.555	−2.285	−0.094
2010 v.s. 2009	0.399	0.528	−0.398	176	0.691	−0.178	0.446	−1.058	0.703
2010 v.s. 2006	17.594	0.000	−3.830	176	0.000	−2.248	0.587	−3.406	−1.090