#setup your working diectory
#all the working files should be here

#change the path to your computer path
#just copy and paste the full path of your working folder
#and make suer to change every "\" into "/"
setwd('U:/STAT380')

#to check where is you current working directory use
getwd()
#the default working directory is in User/My Documents


#generate 1000 samples from binomial distribution with n=100 trials and p of succes =.05
x=rbinom(1000,n=100,prob=0.5)

########################################################################
#save the plot in the file that in the working directory
########################################################################
#start the png device in order to save your plot in a .png image file
png('histogram.png')

#make a histogram and save the object in a variable h
#note: we need prob=TRUE, to get probabiliities not counts in our histogram
hist(x,nclass=20,main='Histogram of Standard normal variable',col='purple',prob=T)

#get the density of the random variable x
d=density(x)
#add density estimate of the distribution of the x on the top of the histogram of x
lines(d,lwd=2, col='red')
abline(v=mean(x),col='green')

#shut off the png device, so that you will be able to open the saved .png image file
#if the device is not shut properly, you might experience problems with accesing the saved file
#and another potential problem might be not showing your plots in your opened R or R Studio instance
dev.off()


#scatterplot of x
plot(x,xlab='x',main='Scatterplot of x')
#plot a density of x
plot(density(x),main='Distribution of x')

##################################################################################
#following is the procedure for installing and 
#loading an R package. This procedure is general to any R package
##################################################################################
#install the package coda using the R command install.packages
install.packages('coda')
#or you can also go to the 'tools/Install packages' menu in R studio and install the 'coda' package  
#or package/install packages in R menu 

#after installing the package, you need to load the package 
#using the command library

library(coda)
#make a traceplot of your chain
traceplot(as.mcmc(x))

#get quantiles of the distribution of x
quantile(x,c(0.25,0.5,0.975))

#save the results in your working directory
#if you want to save in directory other than your working directory, giva a full path 
#for example 'U:/STAT380/x_chain.RData'
save(x,file='x_chain.RData')
#load the saved results from your woking directory.
#give a full path if the file you want to load is in a directory different from your working directory
load('x_chain.RData')