draw Venn diagram
passed test ---- both - did assignment
20-16=4 -------- 16 -------- 19-16 = 3
4 + 16 + 3 = 23 who did something useful
that leaves 28 - 23 = 5 outside your diagram who did nothing
16 out of the 19 who did the homework passed the test
so
16/19 = 0.842
Doing the homework seems to have helped them pass the test.
In a math class with 28 students, a test was given the same day that an assignment was due. There were 20 students who passed the test and 19 students who completed the assignment. There were 16 students who passed the test and also completed the assignment. What is the probability that a student passed the test given that they completed the homework?
1 answer
1 answer