Skip to main content

Table 3 Effect of the environmental variables on AIV cases in wild birds in the contiguous US, 2005-2008.

From: Mapping the risk of avian influenza in wild birds in the US

Effect

Est.

Std. Err.

t-value (df = 132)

p

Intercept

-3.279

0.58

-5.65

<.0001

First day of the year free of ice or snow Range: 0 (snow-free) to day of the year 150

-0.0282

0.0116

-2.43

0.0164

Minimum temperature Range: -7.15 to 19.67°C

-0.2143

0.0734

-2.92

0.0041

Percent harvested cropland per county: Range: 0-100

0.0433

0.00951

4.56

<.0001