# Zelig-probit-bayes-class: Bayesian Probit Regression In Zelig: Everyone's Statistical Software

## Description

Bayesian Probit Regression

## Arguments

 `formula` a symbolic representation of the model to be estimated, in the form `y ~ x1 + x2`, where `y` is the dependent variable and `x1` and `x2` are the explanatory variables, and `y`, `x1`, and `x2` are contained in the same dataset. (You may include more than two explanatory variables, of course.) The `+` symbol means “inclusion” not “addition.” You may also include interaction terms and main effects in the form `x1*x2` without computing them in prior steps; `I(x1*x2)` to include only the interaction term and exclude the main effects; and quadratic terms in the form `I(x1^2)`. `model` the name of a statistical model to estimate. For a list of supported models and their documentation see: http://docs.zeligproject.org/articles/. `data` the name of a data frame containing the variables referenced in the formula or a list of multiply imputed data frames each having the same variable names and row numbers (created by `Amelia` or `to_zelig_mi`). `...` additional arguments passed to `zelig`, relevant for the model to be estimated. `by` a factor variable contained in `data`. If supplied, `zelig` will subset the data frame based on the levels in the `by` variable, and estimate a model for each subset. This can save a considerable amount of effort. For example, to run the same model on all fifty states, you could use: ```z.out <- zelig(y ~ x1 + x2, data = mydata, model = 'ls', by = 'state')``` You may also use `by` to run models using MatchIt subclasses. `cite` If is set to 'TRUE' (default), the model citation will be printed to the console.

## Details

Additional parameters avaialable to this model include:

• `weights`: vector of weight values or a name of a variable in the dataset by which to weight the model. For more information see: http://docs.zeligproject.org/articles/weights.html.

• `burnin`: number of the initial MCMC iterations to be discarded (defaults to 1,000).

• `mcmc`: number of the MCMC iterations after burnin (defaults to 10,000).

• `thin`: thinning interval for the Markov chain. Only every thin-th draw from the Markov chain is kept. The value of mcmc must be divisible by this value. The default value is 1.

• `verbose`: defaults to FALSE. If TRUE, the progress of the sampler (every 10%) is printed to the screen.

• `seed`: seed for the random number generator. The default is `NA` which corresponds to a random seed of 12345.

• `beta.start`: starting values for the Markov chain, either a scalar or vector with length equal to the number of estimated coefficients. The default is `NA`, such that the maximum likelihood estimates are used as the starting values.

Use the following parameters to specify the model's priors:

• `b0`: prior mean for the coefficients, either a numeric vector or a scalar. If a scalar value, that value will be the prior mean for all the coefficients. The default is 0.

• `B0`: prior precision parameter for the coefficients, either a square matrix (with the dimensions equal to the number of the coefficients) or a scalar. If a scalar value, that value times an identity matrix will be the prior precision parameter. The default is 0, which leads to an improper prior.

Use the following arguments to specify optional output for the model:

• `bayes.resid`: defaults to FALSE. If TRUE, the latent Bayesian residuals for all observations are returned. Alternatively, users can specify a vector of observations for which the latent residuals should be returned.

## Value

Depending on the class of model selected, `zelig` will return an object with elements including `coefficients`, `residuals`, and `formula` which may be summarized using `summary(z.out)` or individually extracted using, for example, `coef(z.out)`. See http://docs.zeligproject.org/articles/getters.html for a list of functions to extract model components. You can also extract whole fitted model objects using `from_zelig_model`.

## Examples

 ```1 2 3``` ```data(turnout) z.out <- zelig(vote ~ race + educate, model = "probit.bayes",data = turnout, verbose = FALSE) summary(z.out) ```

Zelig documentation built on March 18, 2018, 2:15 p.m.