Geographical clustering of lung cancer in the province of Lecce, Italy: 1992–2001

Table 2 Tests for assessing the presence of heterogeneity and spatial autocorrelation in the relative risks of mortality for lung cancer in the province of Lecce, 1992–2001

Test	Sampling null distribution	Number of iterations	P-value
Males
Pearson chi-squared	Multinomial	9999	0.01
Pothoff-Whittinghill	Multinomial	9999	0.01
Dean's over-dispersion test			0.01
Geary's C	Negative Binomial	9999	0.03
Moran's I	Negative Binomial	9999	0.01
Females
Pearson chi-squared	Multinomial	9999	0.02
Pearson chi-squared *	Multinomial	9999	0.42
Pothoff-Whittinghill	Multinomial	9999	0.01
Pothoff-Whittinghill *	Multinomial	9999	0.42
Dean's over-dispersion test			0.01
Dean's over-dispersion test*			1.00
Geary's C	Negative Binomial	9999	0.53
Moran's I	Negative Binomial	9999	0.64

Parametric bootstrap under used, when necessary, to compute the significance of the observed values. For Geary's C and Moran's I a Negative Binomial bootstrap sampling distribution under the null hypothesis was used, in order to account for the presence of extra-Poisson variation. For females, some tests were conducted twice: the star '*' means that the test was carried out excluding the Lecce area.

ISSN: 1476-072X