Radish Slaw

My eldest son made this to go with roast beef sandwiches, which it is apparently delicious in, but I liked it just as a side salad.

1/2 lb. shredded radish
1 1/2 Tbs. white vinegar
1 Tsp. kosher salt
1 Tsp. sugar
1 Tbp. olive oil
1 Tbs. horseradish
Parsley to taste

Mix the ingredients together and serve.