Extracts the predicted NEC value as desired from an object of class bayesnecfit or bayesmanecfit.

nec(
  object,
  posterior = FALSE,
  xform = identity,
  prob_vals = c(0.5, 0.025, 0.975)
)

Arguments

object

An object of class bayesnecfit or bayesmanecfit returned by bnec.

posterior

A logical value indicating if the full posterior sample of calculated NEC values should be returned instead of just the median and 95% credible intervals.

xform

A function to apply to the returned estimated concentration values.

prob_vals

A vector indicating the probability values over which to return the estimated NEC value. Defaults to 0.5 (median) and 0.025 and 0.975 (95 percent credible intervals).

Value

A vector containing the estimated NEC value, including upper and lower 95% credible interval bounds (or other interval as specified by prob_vals).

Details

The NEC is a parameter in a threshold model (for example, see Fox 2010), and is a true measure of No-effect-concentration (the minimum concentration above which an effect is predicted to occur.

References

Fox DR (2010). A Bayesian Approach for Determining the No Effect Concentration and Hazardous Concentration in Ecotoxicology. Ecotoxicology and Environmental Safety, 73(2), 123–131. doi: 10.1016/j.ecoenv.2009.09.012.

See also

Examples

library(bayesnec)
data(manec_example)
nec(manec_example)
#> bayesmanecfit contains ecx model types and therefore nec estimate includes nsec values.
#>       Q50      Q2.5     Q97.5 
#> 1.4577088 0.6734928 1.5108440 
#> attr(,"toxicity_estimate")
#> [1] "nec"