1. Load the file "6304 Module 9 Assignment Data.xlsx" into R. This data set includes several variables on 437 counties in six midwestern states. This will be your master data set 2. Create a single data frame for your analysis. This will be your primary data set. It will meet the following characteristics: a. Includes state, popdensity, density.category, percollege, and inmetro variables from the master (N=437) data set. b. Be a random sample of n=250, with each state making up 20% of the total sample. For example, 20% of 250 observations will be from the state of Illinois, 20% from Indiana, etc. Use your U number as the random number seed. c. The variables state, density.category, and inmetro will be factors