Lab_03

state had to adopt it we only need to have one condition, the timing of the policy. Essentially, for every county in the state of Texas, starting in the year 2000, we should have a 1 in the variable column named “Waiting_Period_10_Days” and 0’s for every county from 1993 through 1999. Basically, if the year in the “year” column is greater than or equal to 2000 (the year the policy was imple- mented) then it should have a 1. If not the year in the “year” column is not greater than or equal to 2000 then it should have a 0. Creating dummy/binary variables using the ifelse function with two conditions, only one unit Suppose Tyler county passed and implemented a magazine restriction, where consumers are not permitted to own magazines that hold more than 10 rounds at a time. Tyler county implemented this policy in 2011. texas_crime_2 $ Magazine_Restriction <- ifelse (texas_crime_2 $ county_name == "tyler" & texas_crime_2 $ year >= 2011 , 1 , 0 ) The & symbol in the previous line of code allows us to add a second condition. In this example both conditions must be true in order for the dummy variable to return a 1. If one or both of those conditions if false then the function will return a 0. Creating dummy/binary variables using the ifelse function with two conditions, with multiple units Suppose a few counties wanted to go a step further on the waiting period policy and have people wait two weeks before they could pick up the firearm they purchased. Austin, Baylor, Dallas, and Trinity passed and implemented a two week waiting period in 2004. #Create a character vector of the four counties that implemented the two week waiting period Counties_2004 <- c ( "austin" , "baylor" , "dallas" , "trinity" ) #Create the dummy variable (with two conditions) for the two week waiting period texas_crime_2 $ Waiting_Period_14_Days <- ifelse (texas_crime_2 $ county_name %in% Counties_2004 & texas_crime_2 $ year >= 2004 , 1 , 0 ) The & symbol in the previous line of code allows us to add a second condition. In this example both conditions must be true in order for the dummy variable to return a 1. If one or both of those conditions if false then the function will return a 0. If you wanted to create the dummy variable county by county here is how you could do it: texas_crime_2 $ Waiting_Period_14_Days_2 <- ifelse (texas_crime_2 $ county_name == "austin" & texas_crime_2 $ year >= 2004 , 1 , 0 ) + ifelse (texas_crime_2 $ county_name == "baylor" & texas_crime_2 $ year >= 2004 , 1 , 0 ) + ifelse (texas_crime_2 $ county_name == "dallas" & texas_crime_2 $ year >= 2004 , 1 , 0 ) + ifelse (texas_crime_2 $ county_name == "trinity" & texas_crime_2 $ year >= 2004 , 1 , 0 ) 3