Residual standard deviation for an Emax regression model

Returns the estimated residual standard deviation from the NLS fit. This method is only available for emaxnls objects; there is no analogous quantity for emaxlogistic models.

Usage

# S3 method for class 'emaxnls'
sigma(object, ...)

Arguments

object: An emaxnls object
...: Ignored

Value

A numeric scalar

Details

Under the assumption of normally distributed errors, sigma estimates the standard deviation of the error term in the Emax model. It is computed as the square root of the residual sum of squares divided by the residual degrees of freedom.

Examples

mod <- emax_nls(
  structural_model = rsp_1 ~ exp_1, 
  covariate_model = list(E0 ~ cnt_a, Emax ~ 1, logEC50 ~ 1), 
  data = emax_df,
  opts = emax_nls_options(max_time = 10)
)
sigma(mod)
#> [1] 0.510758