The task is to explore the US census population estimates by county for 2015 from the packageusmap(load the data frame fromcountypop.RData). The data frame has3142rows and4variables:fipsis the 5-digit FIPS code corresponding to the county;abbris the 2-letter state abbreviation;countyis the full county name;pop_2015is the 2015 population estimate (in number of people) for the corresponding county. Each row of the data frame represents a different county or a county equivalent. For the sake of simplicity, when we say a county, that also includes a county equivalent and when we say a state, that also includes the District of Columbia. Answer the following questions.

1. Which state has the largest number of counties? Which state has the smallest number of counties (1 points)?
2. What is the average population of a county in the US (1 point)?
3. Which state has the largest county in terms of population? How many people live in the largest county in terms of population (2 points)?
4. What is the largest county in terms of population of each of the states (2 points)?
5. What is the average population of the 100 largest counties in the US (2 points)?
6. How many people live in each of the states (2 points)?
7. What is the average population of a county in California (2 points)?
8. What is the average population of a county in each of the states (2 points)?