CREATE TABLE table_30155 ("State Rank" FLOAT, "National Rank" FLOAT, "Institution" TEXT, "Location" TEXT, "Public or Private" TEXT, "Endowment Funds" TEXT, "Percentage Change YOY" TEXT)

Name the national rank for medical university of south carolina
SELECT "National Rank" FROM table_30155 WHERE "Institution" = 'Medical University of South Carolina'
SELECT "National Rank" FROM "table_30155" WHERE "Institution" = 'Medical University of South Carolina'