Step 1 :A test was given to a group of students. The grades and shirt colors are summarized in a table.
Step 2 :We are asked to find the probability that a student was wearing a red shirt given that they got a 'C'.
Step 3 :From the table, we can see that the number of students who got a 'C' and were wearing a red shirt is 6.
Step 4 :The total number of students who got a 'C' is 8.
Step 5 :We calculate the probability by dividing the number of students who got a 'C' and were wearing a red shirt by the total number of students who got a 'C'.
Step 6 :The calculation is \( \frac{6}{8} = 0.75 \)
Step 7 :So, the probability that a student was wearing a red shirt given that they got a 'C' is \(\boxed{0.75}\).