R code template for working on homework 3

Homework3Template.R

# Homework 3 R code template 

# Before doing anything else, get a copy of HeartDiseaseDiabetes.csv
# This file is available on the github site, and an excel version is 
# available on icon. Remember that to use the excel version, you need 
# to open it in excel or libre office and save a copy as a csv. 


# Once you have obtained a copy of the data set in csv format, take 
# note of where you've saved it. We need to tell R to use that folder 
# as a working directory. 

# I'm working on a linux machine, so my path will look a lot like 
# one used on a mac. If you don't know how to work with folder paths, 
# email me and we'll work on getting you set up. 


# This is where I'm keeping my section 2 materials:
setwd("/home/grantbrown/dev/171-162-Materials/Section2/")
# A mac path might look something like: 
# setwd("/Users/yourusername/Documents/Homework3")
# A windows path might look something like:
# setwd("C:/Users/yourusername/Documents/Homework3")

# Now we need to read in the data. It's already nicely packaged into a 
# csv file, so there's not much work to do here. I'm going to call 
# my data mortalityData

mortalityData = read.csv("./HeartDiseaseDiabetes.csv", head = TRUE)
# Remember that the option "head = TRUE" tells R to look for variable 
# names. 

# In this homework, we're interested in the log of the variable
# HeartCrude and the variable DiabetesCrude. I'm going to extract 
# these from the data set here, and refer to them as Y and X for clarity. 

Y = log( mortalityData$HeartCrude)
X = mortalityData$DiabetesCrude

# To get a basic scatterplot, I just have to do:

plot(X, Y, 
     main = "Fancy Pants Scatterplot", 
     xlab = "Diabetes Crude Rate per 100k",
     ylab = "log(Heart Crude Rate per 100k)" 
     )


# To get a basic regression, I just use the lm function

myFancyRegression = lm(Y~X)

# To add the regression line to my plot, I just do

abline(reg=myFancyRegression)

# To get a summary of the regression output, I can just type:

summary(myFancyRegression)

# If you want to show your regression output in something like 
# a word file, just copy the text from the R window and then format 
# it with a font like "Courier New", which is monospace (so everything 
# lines up right)