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Table 1 Summary statistics and univariable comparisons using the Mann-Whitney U test, for the variables flock-size, farm-area, density, altitude, mean annual temperature and mean annual rainfall for farms confirmed scrapie-positive (n = 411) and a random sample of scrapie-negative farms (n = 1644) in Great Britain between 1st January 2002 and December 2005.

From: Classical sheep scrapie in Great Britain: spatial analysis and identification of environmental and farm-related risk factors

Variables Scrapie positive
(n = 411)
Scrapie negative
(n = 1644)
P-value
(Mann-Whitney U test)
  Median IQR* Median IQR*  
Altitude (masl)      
   England 140 124 140 136 0.41
   Scotland 86 128 137 151 0.006
   Wales 282 139 241 199 0.002
Flock size (no. sheep)      
   England 312 452 61 196 <0.001
   Scotland 330 479 98 315 <0.001
   Wales 861 764 193 456 <0.001
Farm area (ha)      
   England 78.8 105.6 22.4 77.6 <0.001
   Scotland 129 224.4 36.5 152.7 0.001
   Wales 117.5 101.43 42.5 81.9 <0.001
Density (sheep/ha)      
   England 4.2 5.5 2.9 4.8 <0.001
   Scotland 2.7 3.7 2.6 4.7 0.637
   Wales 7 3.7 5.2 4.6 <0.001
Mean temperature 2002 - 2005 (°C)      
   England 10 1.32 10.1 1.06 0.306
   Scotland 8.7 0.55 8.8 1.01 0.544
   Wales 9.5 1.18 9.8 1.23 0.014
Mean rainfall 2002 - 2005 (mm)      
   England 73.4 37.6 69.6 31.2 0.204
   Scotland 82 19.59 98.7 39.4 <0.001
   Wales 112.1 46.72 103.9 35 0.006
  1. * IQR = interquartile range