---
title: "Assignment 1 - SAT"
author: "Nikola Danevski"
date: "9/14/2019"
output: pdf_document
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

We plot SAT score against professor salary below.
There is no relationship between the two entries (although one could argue it is weak, linear and negative).
1 = "black", 2 = "red", 3 = "green". The plot says that #TODO WHAT EXACTLY

```{r}
sat <- read.csv("SAT.csv")
head(sat)
#TODO what does c) ask us to do?
cor(sat$salary, sat$sat)
group_frac <- cut(sat$frac, breaks=c(0,22,49,81), labels = c(1,2,3))
plot(x = sat$salary, y = sat$sat, xlab = "Salary of the professor", ylab = "Sat score", col = group_frac)
cor(sat$salary[group_frac == 1], sat$sat[group_frac == 1])
cor(sat$salary[group_frac == 2], sat$sat[group_frac == 2])
cor(sat$salary[group_frac == 3], sat$sat[group_frac == 3])

expendCAT <- ifelse(SAT$expend > 7, "high", "low")
sat900 <- ifelse(SAT$sat > 900, "Higher", "Lower")




```