model_selection.R

data <- read.csv("manhours.csv",header=T)
library(MASS)
library(car)
library(leaps)
attach(data)
pairs(data)

# The data concern the manpower and workload for US Navy Bachelor Officers' Quarters
# Estimate manpower needs for manning Bachelor Officers Quarters. 
# Site: Site id
# ocup: Average Daily Occupancy
# check: Monthly number of check-ins
# service: Weekly hours of service desk operation
# sqfoot: Square feet of common area use
# wings: Number of building wings
# cap: Operational berthing capacity
# rooms: Number of rooms
# hours: Monthly man hours (The Y variable)
#
# Backwards Manual
#
boxcox(lm(hours~ocup+check+service+sqfoot+wings+cap+rooms))
summary(lm(hours~ocup+check+service+sqfoot+wings+cap+rooms))
#
# Automated Stepwise
#
stepAIC(lm(hours~ocup+check+service+sqfoot+wings+cap+rooms,subset=c(-24)))
length(hours)
stepAIC(lm(hours~ocup+check+service+sqfoot+wings+cap+rooms,subset=c(-24)),k=log(24))
res <- stepAIC(lm(hours~ocup+check+service+sqfoot+wings+cap+rooms,subset=c(-24)),k=log(24))
summary(res)
#
# Forward
#
summary(lm(hours~ocup,subset=c(-24)))
summary(lm(hours~check,subset=c(-24)))
summary(lm(hours~service,subset=c(-24)))
summary(lm(hours~sqfoot,subset=c(-24)))
summary(lm(hours~wings,subset=c(-24)))
summary(lm(hours~cap,subset=c(-24)))
summary(lm(hours~rooms,subset=c(-24)))
#
# Automated
# 
stepAIC(lm(hours~1,subset=c(-24)),scope=(~ocup+check+service+sqfoot+wings+cap+rooms),direction="forward")
stepAIC(lm(hours~1,subset=c(-24)),scope=(~ocup+check+service+sqfoot+wings+cap+rooms),direction="forward",k=log(24))
stepAIC(lm(hours~1,subset=c(-24)),scope=(~ocup+check+service+sqfoot+wings+cap+rooms),direction="both",k=log(24))
#
# Best subsets
#
res <- regsubsets(hours~ocup+check+service+sqfoot+wings+cap+rooms,data=data[-24,])
summary(res)
summary(res)$bic
plot(res)
#
#
#
res <- stepAIC(lm(hours~(ocup+check+service+sqfoot+wings+cap+rooms)^2,subset=c(-24)),k=log(24))
summary(lm(hours~(ocup+check+service+sqfoot+wings+cap+rooms)^2))
res <- stepAIC(lm(hours~(ocup+sqfoot+wings+cap+rooms)^2+check+service,subset=c(-24)),k=log(24))
summary(res)
res <- stepAIC(lm(hours~1,subset=c(-24)),scope=(~(ocup+sqfoot+wings+cap+rooms+check+service)^2),direction="forward",k=log(24))
summary(res)
ressub <- regsubsets(hours~(ocup+check+service+sqfoot+wings+cap+rooms)^2,data=data[-24,],nvmax=20)
summary(ressub)$bic
summary(ressub)
summary(lm(hours~ocup+check+service+sqfoot+rooms+ocup:check+ocup:service+ocup:sqfoot+ocup:cap+
                 check:wings+check:cap+service:sqfoot+service:wings+service:cap+sqfoot:wings+
                 sqfoot:rooms+wings:rooms,subset=c(-24)))
summary(lm(hours~ocup+check+service+sqfoot+rooms+ocup:check+ocup:service+ocup:sqfoot+ocup:cap+
                 check:wings+check:cap+service:wings+service:cap+sqfoot:wings+
                 sqfoot:room
s+wings:rooms,subset=c(-24)))
res<-lm(hours~check+sqfoot+rooms+ocup:service+ocup:sqfoot+
                 check:cap+service:cap+sqfoot:wings+
                 sqfoot:rooms,subset=c(-24))
summary(res)
plot(res,1)