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


```{r echo = FALSE, message = FALSE}
library(tidyverse)
options(scipen = 999)

arthritis <- read_csv("https://raw.githubusercontent.com/cosmos-uci-dshs/data/main/RheumArth_Tx_AgeComparisons.csv") %>% 
  janitor::clean_names() %>% 
  mutate(sex = case_when(sex == 0 ~ "female",
                   sex == 1 ~ "male")) %>% 
  mutate(sex = as.factor(sex)) %>% 
  mutate(age_gp = case_when(age_gp == 1 ~ "control",
                   age_gp == 2 ~ "elderly")) %>% 
  mutate(age_gp = as.factor(age_gp)) %>% 
  mutate(cdai_yn = case_when(cdai_yn == 1 ~ "no",
                             cdai_yn == 2 ~ "yes")) %>%
  mutate(cdai_yn = as.factor(cdai_yn))
```

## Usual Practice
1. If you are asked to install any packages install them by clicking the "Install" button in the yellow banner.
2. Always start by knitting any `.Rmd` file to make sure everything looks good. 
3. Always run R chunks provided to you before moving onto the rest of the document.
4. Write the [YAML part of](https://cosmos-uci-dshs.github.io/dshs-slides/week01/01b-intro-r.html#26) this document. 

---

Write out the examples from the slides. 
Do not copy-paste. 
Part of the learning process is making typos and trying to fix them.