one_source_priors_params: Adjust Bayesian priors - One Source Trophic Position

In trps: Bayesian Trophic Position Models using 'stan'

Adjust Bayesian priors - One Source Trophic Position

Description

Adjust priors for one source trophic position model derived from Post 2002.

Usage

one_source_priors_params(
  n1 = NULL,
  n1_sigma = NULL,
  dn = NULL,
  dn_sigma = NULL,
  tp_lb = NULL,
  tp_ub = NULL,
  sigma_lb = NULL,
  sigma_ub = NULL,
  bp = FALSE
)

Arguments

n1	mean (\mu) prior for the mean \delta^{15}N baseline. Defaults to 9.
n1_sigma	variance (\sigma) for the mean \delta^{15}N baseline. Defaults to 1.
dn	mean (\mu) prior value for \DeltaN. Defaults to 3.4.
dn_sigma	variance (\sigma) for \delta^{15}N. Defaults to 0.25.
tp_lb	lower bound prior for trophic position. Defaults to 2.
tp_ub	upper bound prior for trophic position. Defaults to 10.
sigma_lb	lower bound prior for \sigma. Defaults to 0.
sigma_ub	upper bound prior for \sigma. Defaults to 10.
bp	logical value that controls whether informed priors are supplied to the model for \delta^{15}N baseline. Default is FALSE meaning the model will use uninformed priors, however, the supplied data.frame needs values for \delta^{15}N baseline (n1).

Details

\delta^{15}N = \delta^{15} N_1 + \delta N \times (tp - \lambda_1)

This function allows the user to adjust the priors for the following variables in the equation above:

• The mean (n1; \mu) and variance (n1_sigma; \sigma) for the mean \delta^{15}N for a given baseline (\delta^{15}N_1). This prior assumes a normal distribution.

• The mean (dn; \mu) and variance (dn_sigma; \sigma) of \DeltaN (i.e, trophic enrichment factor). This prior assumes a normal distribution.

• The lower (tp_lb) and upper (tp_ub) bounds for trophic position. This prior assumes a uniform distribution.

• The lower (sigma_lb) and upper (sigma_ub) bounds for variance (\sigma). This prior assumes a uniform distribution.

Value

stanvars object to be used with brms() call.

See Also

one_source_priors(), one_source_model(), and brms::brms()

Examples

one_source_priors_params()

trps documentation built on April 4, 2025, 12:20 a.m.