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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