1. Find the mean marks of the students for the following distribution; Number of Number of Marks Marks Students Students 0 and above 80 80 60 and above 28 10 and above 77 70 and above 16 20 and above 72 30 and above 65 40 and above 55 50 and above 43 80 and above 10 90 and above 8 100 and above 0