Table 2.

Standardized Coefficients for Regression Analyses Peformed with Relative Humidity or Absolute Humidity. Comparison of the standardized coefficients allow the magnitude of the effect of each parameter to be directly compared. For the range of environmental conditions tested, sunlight had the greatest influence on the decay constant for infectivity in either model, followed by temperature and their interaction. Humidity, regardless of whether it was expressed as relative or absolute humidity, had the smallest influence on the decay constant for infectivity. Best fit values are presented with 95% confidence intervals for each coefficient in parentheses underneath.

	Standardized Regression Coefficients
Environmental Parameter	Model with Relative Humidity	Model with Absolute Humidity
Temperature (C)	0.04018 (0.1788 to 0.06247)	0.02218 (−0.00154 to 0.04589)
Simulated Sunlight (W/m2 UVB)	0.14369 (0.12620 to 0.16118)	0.14488 (0.12771 to 0.16205)
Relative Humidity (%)	0.02176 (0.00980 to 0.03372)	NA
Absolute Humidity (g-H2O/m3-air)	NA	0.03955 (0.01973 to 0.05937)
Temperature (°C) × Solar (W/m2 UVB)	0.02636 (0.00292 to 0.04981)	0.02624 (0.00321 to 0.04926)