## Add a Directory HW8

Add a directory HW8 to your repository. This is where you will put the rest of your work for this assignment.

Be sure to commit and push your changes.

## 1. Air Pollution Data

The SemiPar package contains a data set calif.air.poll with measurements of ozone level and several covariates for 345 days. You can load the data set with

data(calif.air.poll, package = "SemiPar")

The help page available with ?SemiPar::calif.air.poll contains more information about the data.

• Create a scatterplot matrix for the variables in the data set and comment on any interesting features you see.

• Use conditioning plots to explore how the relationship between ozone.level and inversion.base.temp changes as daggett.pressure.gradient increases.

## 2. Olive Oils

For the olive oils data set used in the class notes consider the subset of the data for oils from the "North" Region. Use parallel coordinate plots and scatterplots to investigate how well the variables separate oils from the "Umbria" Area from oils from the other two areas in the "North" Region.

If the extracat package is not available you can also obtain the data from a CSV file with

olives <- read.csv("http://homepage.divms.uiowa.edu/~luke/data/olives.csv")

Write up your work in an Rmarkdown document called hw8.Rmd in your HW8 folder, and commit it to your local repository. You can commit the hw8.html file as well but you do not need to.

## Make Sure Your Work Is Reproducible

One of the goals of using git, GitHub, and Rmarkdown is for you to practice creating a framework that you can hand to someone else to reproduce your analysis. This means, among other things, that

• you should not make use of files from your computer outside of your repository;

• you should not rely on being able to change the working directory to your home directory;

• you should assume that your code might be run an a case-sensitive file system.

If you are working on Windows or a Mac a good test is to go to our Linux systems, check out your repository, and check that your hw8.Rmd file can be rendered successfully to produce hw8.html. You can do this using the RStudio menus or from the R command line with

rmarkdown::render("hw8.Rmd")

Make sure your working directory is HW8 for this.

You can also run this command in a shell in your HW8 directory:

Rscript -e 'rmarkdown::render("hw8.Rmd")'

Make sure you use the right combination of single and double quotes.