Use an appropriate function to create a new variable in the "lahman" data frame called "RD" (run differential) that is calculated as R-RA (runs scored by a team minus runs scored by a team's opponents).

(writing code in Positcloud or Rstudio)

Use an appropriate function to create a new variable in the "lahman" data frame called "Wpct" (win percentage) that is calculated as (100*W/G).

(Writing code in PositCloud or Rstudio)