Iowa (22-12) will next take on Stony Brook in the second round after the Seawolves pulled off a 71-58 upset of Massachusetts on Wednesday.
The Hawkeyes held a one-point lead at halftime, then outscored Indiana State 19-4 over the first 9:30 of the second half.
Marble scored 24 points, pulled down five rebounds and added six assists. Aaron White was the only other Iowa player in double figures with 11 points. Iowa won one game in the Big Ten Conference Tournament before losing to Nebraska.
Indiana State, which fell to Northern Iowa in the first round of the Missouri Valley Conference tourney, finished its season at 18-15. Justin Gant scored 16 points to lead the Sycamores, who shot just 38 percent from the field and went 4-of-17 from 3-point range.