A university has 4 different instructors teaching calculus 1. There have been complaints from students that one of the 4 instructors fail too many students and complaints from professors that one...

A university has 4 different instructors teaching calculus 1.  There have been complaints from students that one of the 4 instructors fail too many students and complaints from professors that one instructor gives too many A’s.  The table (photo attached below) gives the number of ABC’s each professor gives along with the number of DFW’s.  3 sections for each teacher were randomly selected over the past 5 years for these values.

Part 1) Test to see if the percent of students receiving an AB or C is different for the different instructors

Part 2) If it is not the same create confidence interval using difference in proportions to find which ones are different from the others. HINT:  start with the largest difference in percents first and work your way in.

Thank you for your help!!