Logical Indexing Grades My Solutions One of the things that instructors pay a lot of attention to, is something called the DFW rate. This includes the number of Ds, Fs, and Ws (withdrawals) in a class. We all want to see this number as low as possible. Using the gradebook generated with the following randomization code, and assuming that each row is a student while each column is an assignment, answer the following questions. grades = round(60*rand(50.15)) + 40; How many Ds or Fs on assignments did the first student receive? Save this to Answer1. (note, use logical indexing for this, a comparator on an array) How many Ds on assignments did the entire class receive? Save this to Answer2. How many students received a D or F in their class final grade? Save this to Answer3. (note, use the mean() function to find the average grade for all students, assuming all assignments are equally weighted) How many Ds or Fs did the students, on average, receive as a final grade? Save this to Answer4. (note, you need to first figure out who received a D or F, and then find what the fraction of entire class that this represents. Was it 0.1 students? That would be 1 in 10. Was it 0.2? Something else?) If the average number of final grade Ds or Fs exceeds 0.1, then assign Answers to 1, and otherwise set Answers to 0. Assume the following grade cutoffs: A is >= 90 B is = 80 C is = 70 Dis = 60 Fis = 90 B is = 80 C is = 70 Dis = 60 Fis