get_condition_post: Combine coefficient samples from a Stan model with the design...
In mike-lawrence/ezStan: Helper Functions for Stan

Combine coefficient samples from a Stan model with the design matrix to compute posterior samples on the conditions of the design.

get_condition_post(
  from_stan,
  par,
  X = NULL,
  W = NULL,
  B = NULL,
  numeric_res = 0,
  collapse_intercept_to_median = FALSE
)

`from_stan`	A stanfit object from a call to rstan::stan() or rstan::sampling() containing posterior samples from the model.
`par`	Character string naming the parameter on which to compute the summary table.
`X`	Optional contrast matrix as yielded from get_contrast_matrix() indicating the contrasts passed as data when creating the above stanfit object.
`W`	Optional contrast matrix as yielded from get_contrast_matrix() indicating the within-subjects contrasts passed as data when creating the above stanfit object. If present, X is ignored and B must be present.
`B`	Optional contrast matrix as yielded from get_contrast_matrix() indicating the between-subjects contrasts passed as data when creating the above stanfit object. W must be present, else B is ignored.
`numeric_res`	Integer value conveying the number of points within the range of a continuous variable to sample. If 0, the values from the data are used.
`collapse_intercept_to_median`	Logical indicating whether to use the median of the samples for the intercept rather than its full set of samples. Assumes that the intercept is the first parameter.