Testing if there is a dose effect at all

A significance test is provided for the comparison of the dose-response model considered and the simple linear regression model with slope 0 (a horizontal regression line corresponding to no dose effect)

noEffect(object)

Arguments

object	an object of class 'drc'.

Details

Perhaps useful for screening purposes.

Value

The likelihood ratio test statistic and the corresponding degrees of freedom and p-value are reported.

Examples

ryegrass.LL.4 <- drm(rootl ~ conc, data = ryegrass, fct = LL.4())

noEffect(ryegrass.LL.4)
#> Chi-square test              Df         p-value 
#>        91.87776         3.00000         0.00000 
# p-value < 0.0001: there is a highly significant dose effect!