posterior_x_at_fy — posterior_x_at

Find the posterior distribution of the value of a predictor variable at a particular point along the derivative. For instance, one might be interested in knowing the age value at which a slope is steepest, or closest to zero.

posterior_x_at_fy(
  object,
  term,
  n,
  eps,
  find = c("min", "max", "value"),
  value = NULL,
  multimodal = TRUE,
  adjust = 1,
  prob = 0.95,
  summary_only = FALSE
)

posterior_x_at_miny(...)

posterior_x_at_maxy(...)

posterior_x_at_yequalto(...)

Arguments

object	a `brmsfit` object
term	character; the smooth term for which the derivative is required.
n	numeric; the number of points to evaluate the derivative at.
eps	numeric; the finite difference.
find	the spot along the derivative to find; can be 'min', 'max', or 'value', in which case the `value` parameter must be set.
value	if `find` is set to 'value', this must be set to a specific value, like 0.
multimodal	if the expected posterior might be multimodal, set this to `TRUE` so that the summary is a true, possibly discontinuous, highest posterior density interval.
adjust	passed to `density` to adjust bandwidth.
prob	the proportion of mass within the HPDI
summary_only	set this to `FALSE` if you want all samples returned.

Value

An object of class curvish.param that contains the summary from hdi, and the posterior samples. If summary_only is TRUE, the only the output from hdi is returned.

Details

posterior_x_at_miny, posterior_x_at_maxy, and posterior_x_at_yequalto are aliases of posterior_x_at_fy where find is set to 'min', 'max', or 'value', respectively and are provided in case they make for more readable code.