Example draws to use in demonstrations and tests

Description

These functions return various objects containing data used in the examples throughout the bayesplot package documentation.

Usage

example_mcmc_draws(chains = 4, params = 4)

example_yrep_draws()

example_y_data()

example_x_data()

example_group_data()

Arguments

Details

Each of these functions returns an object containing data, parameter draws, or predictions corresponding to a basic linear regression model with data y (outcome vector) and X (predictor matrix), and parameters alpha (intercept), beta (coefficient vector), and sigma (error sd).

example_mcmc_draws

If chains > 1, a 250 (iterations) by chains by params array or, if chains = 1, a 250 by params matrix of MCMC draws from the posterior distribution of the parameters in the linear regression model described above. If params = 1 then only the draws for alpha are included in the returned object. If params >= 2 then draws for sigma are also included. And if params is between 3 and the maximum of 6 then draws for regression coefficients beta[k] (k in 1:(params-2)) are also included.

example_y_data

A numeric vector with 434 observations of the outcome variable in the linear regression model.

example_x_data

A numeric vector with 434 observations of one of the predictor variables in the linear regression model.

example_group_data

A factor variable with 434 observations of a grouping variable with two levels.

example_yrep_draws

A 500 (draws) by 434 (data points) matrix of draws from the posterior predictive distribution. Each row represents a full dataset drawn from the posterior predictive distribution of the outcome y after fitting the linear regression model mentioned above.

Value

See Details.

Examples

draws <- example_mcmc_draws()
dim(draws)
dimnames(draws)

draws <- example_mcmc_draws(1, 2)
dim(draws)
colnames(draws)

draws <- example_mcmc_draws(params = 6)
dimnames(draws)[[3]]

y <- example_y_data()
x <- example_x_data()
group <- example_group_data()
length(y)
length(x)
length(group)
tail(data.frame(y, x, group), 5)

yrep <- example_yrep_draws()
dim(yrep) # ncol(yrep) = length(y) = length(x) = length(group)