R_programming_synchronous_9.17.20.Rmd

---
title: 'Sep 17 Synchronous Session'
author: 'Data Science for Biomedical Informatics (BMIN503/EPID600)'
output: 
  html_document:
    theme: cerulean
    highlight: pygments
---

***

### COVID in Philadelphia

1. Load data frames called `covid.jul` and `covid.aug` corresponding to covid test results reported by the Philadelphia Department of Public Health on July 7 and August 11, 2020 that are in files `phl_covid_tests_7.7.20.txt` and `phl_covid_tests_8.11.20.txt`, respectively.

```{r, eval = TRUE}
```

2. How many COVID-19 test results had been reported in Philadelphia by August 11? 
```{r, eval = TRUE}
```

3. What zip code had the greatest number of positive tests by August 11?
```{r, eval = TRUE}
```

4. Create a function `most.neg` that returns the zip code with the greatest number of negative tests along with that number as a data frame. Use the function to get this output for July 7 and Aug 11.
```{r, eval = TRUE}
```


***