POL 304: Using Data to Understand Politics and Society

class: center, middle, inverse, title-slide

.title[
# POL 304: Using Data to Understand Politics and Society
]
.subtitle[
## Lab 1: Intro to R
]
.author[
### Olga Chyzh [www.olgachyzh.com]
]

---

## Always Start By...

- Navigating to your working directory 
<img src="images/change_dir.jpg" width="1100px" style="display: block; margin: auto;" />

---
## And ...

- Setting your directory
<img src="images/set_dir.jpg" width="1100px" style="display: block; margin: auto;" />

---
## Open Data Files

- To open `.csv` files, use `read.csv`

```r
rosca<-read.csv('./data/rosca.csv', header=TRUE)
```

---
## Access/Create a New Variable

```r
rosca$bg_female

rosca$new_var<- NA
```
---
## Subset Rows by Value

Suppose you want to see the values of the `fol2_amtinvest` variable only for women.

```r
rosca$fol2_amtinvest[rosca$bg_female==1]

##Or create a copy of the dataset that only includes women:
rosca1<- rosca$fol2_amtinvest[rosca$bg_female==1]
```
---
## Calculate the Mean

```r
mean(rosca$fol2_amtinvest, na.rm=TRUE)
mean(rosca$fol2_amtinvest[rosca$bg_female==1], na.rm=TRUE)

tapply(rosca$fol2_amtinvest, rosca$bg_female,mean, na.rm=TRUE)
```
---

## Tabulate Observations by Category

```r
table(rosca$bg_female)
```

---
## Your Turn

Create a single variable `treatment` that takes the value `control` for observations that received only encouragement, `safebox` if received a safe box, and `lockbox` if receiving a locked box. How many individuals are in the control group? How many individuals are in each of the treatment groups?

---
## Challenge Yourself

- Run the code below to install the `qss-package` and `qss.student` packages that go with the textbook.

```r
library(devtools)
devtools::install_github("kosukeimai/qss-package", build_vignettes = TRUE)
devtools::install_github("conjugateprior/qss.student")
library(qss)
library(qss.student)
```

- Run the code below to access the files that go with today's lab. This will put the files into a folder named "health-savings" in the directory you specified in 1.

```r
get_pset("health-savings")
```

- Complete the problem set.