##############################################

#

# HOW TO USE THIS FILE

# A text version of this file (ex5.R) is also available which can just be sourced

# into the R program

# This file is intended for you to use interactively by pasting into R

# Comments are in black - red bits are commands that can be pasted into R

# 

#

#########  ANY TEXT AFTER THE # CHARACTER ARE TREATED AS COMMENTS

#

# data stored in c:/GR/aprojects/peas/web/exemp3/data/ex5wt.Rdata

# this file is c:/GR/aprojects/peas/web/exemp3/program_code/ex5wt_R.html

#

##############################################

#

# data are in a data frame data

# to get the names of the variables

#

names(data)

#

# look at the first 5 rows

data[1:5,]

#

# now a logistic regression of response rates

# only the final model is shown here though the other could readily  be explored

#

resp<-glm(cbind(AyrA_num,npop)~agegrp+gender+agegrp*agegrp+agegrp*gender+agegrp*agegrp*gender+sinc+sacc+

                                             agegrp*sinc+agegrp*agegrp*sinc,data=data,family=binomial)

print(summary(resp))

#

# we now get the linear predictor

#

lp<-predict(resp)

#

# and make it into a predicted probability

#

phat<-1/(1+exp(-lp))

#

 # and get the grossing weight and add to the data frame

#

data$gweight<-1/phat

#

# this can then be merged back to the main file

#