#### Quant 1
#### Week 1 Code

# show what we can do with R
packages    <- c("SPSS","Excel","Stata","R")
features    <- c(25,50,100,150)
cost        <- c(100,50,90,0)
barplot(features, names.arg=packages, ylab="Feature index")
plot(features, -cost, xlab="Feature Index", ylab="(Inverse) Cost Index")
text(features, -cost, packages, pos=c(4,4,4,2))


#######################
#####Dail example######
#######################


# load in the Dail 2002 candidate spending data
load("dail2002.Rdata")
# tabulate incumbency status by victory
attach(dail2002)
table(incumbf,wonseatf)

# produce a mean for each candidate category
tapply(spend_total, incumbf, mean)

# perform a t-test of difference
t.test(spend_total ~ incumbf)

# plot spending by candidate category
plot(spend_total ~ incumbf)


#######################
### Birthday example###
#######################


lbdp <- function(n) {
1 - exp(lfactorial(365) - lfactorial(365-n) - n*log(365))
}
x <- 1:60
plot(x,lbdp(x))
plot(x,lbdp(x),
xlab="Number of people",ylab="Probability of same birthday")
abline(h=.5, lty="dashed", col="red")