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.

Mr. Jones Ms. Smith Dr. Potts Dr. Willis ABC 108 112 96 100 DFW 20 15 30 23