##############################
#
# Script for Homework 12
#
##############################


#####
# Standard preamble

crime <- read.csv("crime.csv", header=TRUE)
names(crime)



#####
# Problem 12.1

south1990 <- crime$vcrime90[crime$census4=="South"]
south2000 <- crime$vcrime00[crime$census4=="South"]

mean(south1990)
mean(south2000)
var(south1990)
var(south2000)

var.test(south1990,south2000)

t.test(south1990,south2000, paired=TRUE)



#####
# Problem 12.2

cr <- crime$vcrime90
em <- crime$unemp90

mean(cr)
mean(em)
var(cr)
var(em)

cov(cr,em)
cor(cr,em)

cor.test(cr,em)



#####
# Problem 12.3

mor <- crime$pcrime00[crime$cultdom=="Moralistic"]
tra <- crime$pcrime00[crime$cultdom=="Traditionalistic"]
ind <- crime$pcrime00[crime$cultdom=="Individualistic"]

mean(mor)
mean(tra)
mean(ind)

var(mor)
var(tra)
var(ind)

var.test(mor,tra)
var.test(mor,ind)
var.test(tra,ind)

t.test(mor,tra, var.equal=TRUE)
t.test(mor,ind, var.equal=TRUE)
t.test(tra,ind, var.equal=TRUE)



#####
# Problem 12.4

pcr00 <- crime$pcrime00
pcr90 <- crime$pcrime90

mean(pcr00)
mean(pcr90)

pcr00[crime$state=="Oklahoma"]
pcr90[crime$state=="Oklahoma"]

t.test(pcr00, mu=4060.8)
t.test(pcr90, mu=5051.2)