If you have a nominal variable that has more than two levels, you need to create multiple dummy variables to take the place of the original nominal variable. For example, imagine that you wanted to predict depression from year in school: freshman, sophomore, junior, or senior.
Washington Post, Redskinsâ Kirk Cousins played a round of golf with President Trump, June 14, 2017. The Hill, Trump plays 18 holes of golf at Virginia club, June 25, 2017. Washington Post, Trump had a terrible July, but at least he played a lot of golf, July 31, 2017. Washington Post, Trump seen at his N.J. golf course, Aug. 7, 2017
During his first getaway as president, Mr. Trump attended the annual Red Cross gala and may or may not have hit a few golf balls. Trump International Golf Club West Palm Beach, Fla. The White House would not confirm whether Mr. Trump had played golf. Trump International Golf Club West Palm Beach, Fla.