Please use R to answer the following questions,

1. What is the *proportion* of counties in each state that has had zero deaths? In other words: in each state, how many counties have had 0 deaths (divided by the total number of counties in the state)? You should produce a *data frame* with columns `state` (containing the statename) and `proportion` (containing the ratio as a decimal), saving that data frame in a variable `proportion_no_deaths_df`. Note: work through it in steps.
2. What proportion of counties in Washington state has had zero deaths? Use your `proportion_no_deaths` data frame, and save your result in `wa_prop_no_deaths`.

data source:

https://github.com/nytimes/covid-19-data/

Please load (us-counties.csv) data set from above website and create data frame

or

county_df <- read.csv("https://raw.githubusercontent.com/nytimes/covid-19-data/master/us-counties.csv")

county_df <- unite(county_df, col="county_state", county, state, sep=",", remove = FALSE) # create new column that store a string of the county and state names together

`tidyverse` package

Addition notes:

you can use the `group_by()` function to perform the same computation simultaneously across groups of rows. Your variables may need to include the specific column or value being asked for (use `pull()`).