library(gdata)
setwd('/Users/akif/Desktop/Dropbox/Courses/ie306/ass2')
d1 <- read.xls('IE306_HW2_data.xls', sheet = 1)
d1 <- d1[[3]]
d1 <- d1[0:-1]

print(sprintf("Standard Deviation: %f", sd(d1)))
print(summary(d1))

hist(d1, breaks=50, main = "Histogram of Day 1 with 50 breaks")
dev.new()
hist(d1, breaks=100, main = "Histogram of Day 1 with 100 breaks")
dev.new()
hist(d1, breaks=200, main = "Histogram of Day 1 with 200 breaks")

expd <-
x2 <- chisq.test(d1, rexp(length(d1), 1/mean(d1)), simulate.p.value=TRUE, B=6, p=rep(1/6,6))
print("H0: Data is exponentially distributed")
if (x2$p.value < qchisq(0.95, 4)) {
    print("reject H0")
} else {
    print("accept H0")
}

r <- 1/mean(d1)
dev.new()
n <- length(d1)
qqplot(rexp(n,r), d1)
qqline(d1, distribution=qexp)

dev.new()
plot(diff(d1, lag=1), type="p", col=1)
points(diff(d1, lag=2), col=2, pch="o")