A sample of midterm grades for five students showed the following results: 68, 61, 78, 86, 72. Which of the following statements are correct, and which should be challenged as being too generalized?
1) Statement 1: The average grade is above 70.
2) Statement 2: All students scored above 60.
3) Statement 3: The highest grade is 86.
4) Statement 4: The lowest grade is 61.