GasolineYield: Gasoline Yields Data

In zoib: Bayesian Inference for Beta Regression and Zero-or-One Inflated Beta Regression

Gasoline Yields Data

Description

GasolineYield contains proportion of crude oil converted to gasoline after distillation and fractionation.

Usage

data(GasolineYield)

Format

A data frame with 32 observations on the following 3 variables.

yield

a numeric vector; proportion of crude oil converted to gasoline after distillation and fractionation.

temp

a numeric vector: temperature (F) at which 100% gasoline has vaporized.

batch

crude oil batch ID.

Details

The Gasoline Yields Data is a subset of the data GasolineYield in R package "betareg". Refer to the detailed description in R package "betareg".

Examples

  ## Not run: 
  library(zoib)
  data("GasolineYield", package = "zoib")
  
  #################################################
	#  fixed effects zoib with 
  #  batch as a 10-level qualitative variable
  ################################################

  eg.fixed <- zoib(yield ~ temp + as.factor(batch)| 1, 
              data=GasolineYield, joint = FALSE,  random = 0, 
              EUID = 1:nrow(d), zero.inflation = FALSE, 
              one.inflation = FALSE, n.iter = 1100, n.thin = 5, 
              n.burn=100)
  # yields 400 posterior draws (200 per chain) on the model parameters
  coeff <- eg.fixed$coef
  summary(coeff)
 
  ### check on convergence
	traceplot(coeff)
	autocorr.plot(coeff)
	check.psrf(coeff)
	   
  ### Design Matrix: Xb, Xd, Xb0, Xb1
  eg.fixed$Xb; eg.fixed$Xd;  eg.fixed$Xb0; eg.fixed$Xb1  
  
  # plot posterior mean of y vs. observed y to check on goodness of fit.
  ypred = rbind(eg.fixed$ypred[[1]],eg.fixed$ypred[[2]])
  post.mean= apply(ypred,2,mean); 
  plot(GasolineYield$yield, post.mean, col='blue',pch=2); 
  abline(0,1,col='red')
  
  ######################################################
  #  mixed effects zoib with batch as a random variable
  #####################################################
  eg.random <- zoib(yield ~ temp | 1 | 1, data=GasolineYield,
                  joint = FALSE, random=1, EUID=GasolineYield$batch,
                  zero.inflation = FALSE, one.inflation = FALSE,
                  n.iter=3200, n.thin=15, n.burn=200)
  sample2 <- eg.random$coeff
  summary(sample2)
  
  # check convergence on the regression coefficients
  traceplot(sample2)
  autocorr.plot(sample2) 
  check.psrf(sample2)
  
  # plot posterior mean of y vs. observed y to check on goodness of fit.
  ypred = rbind(eg.random$ypred[[1]],eg.random$ypred[[2]])
  post.mean= apply(ypred,2,mean); 
  plot(GasolineYield$yield, post.mean, col='blue',pch=2); 
  abline(0,1,col='red')
	
## End(Not run)

zoib documentation built on May 31, 2023, 7:49 p.m.