Table 3.

Chi-square analysis of differences in Penicillium distribution ratios between the underground and London locations

Ratio comparisona	Location	Central Line	Jubilee Line	Outdoors	St Mary's hospital
C:R	Bakerloo Line	0.138	0.171	0.388	0.382
Central Line	X	0.887	0.883	0.858
Jubilee Line	X	X	0.945	0.793
Outdoors	X	X	X	0.814
C:O	Bakerloo Line	0.056	0.609	0.084	0.905
Central Line	X	0.286	*0.004	0.138
Jubilee Line	X	X	*0.048	0.613
Outdoors	X	X	X	0.138
R:O	Bakerloo Line	*0.000	*0.020	0.536	0.304
Central Line	X	0.310	*0.002	0.065
Jubilee Line	X	X	*0.026	0.360
Outdoors	X	X	X	0.180
C + R:O	Bakerloo Line	*0.000	0.066	0.098	0.578
Central Line	X	0.185	*0.000	*0.029
Jubilee Line	X	X	*0.005	0.342
Outdoors	X	X	X	0.058

p values (<0.05 highlighted by *) from the Chi-square test for independence indicate differences in the ratios of Penicillium between locations. No statistical difference was shown between locations in the ratio of P. chrysogenum to P. rubens. The Central and Jubilee Line were consistently different to the Outdoors in the other Penicillium ratios.

^aRatio comparison abbreviations, C = Chrysogenum, R = Rubens, O = Other Penicillium.