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

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

bnec

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 
#> 1.4503481 0.7487292 1.5273698 
#> attr(,"toxicity_estimate")
#> [1] "nec"