A Professor Gives a Special Tutoring Session to Students Who

Multiple Choice

A professor gives a special tutoring session to students who scored less than 60 percent on the first test.On the second test,their mean score rises to 70 percent.What conclusion can we draw,if any,and why?

A) The tutoring helped, as we see from the higher scores.
B) The tutoring helped, because without it those students would have been discouraged.
C) We should draw no conclusion, because there was no control group.
D) We should draw no conclusion, because the study had too many independent variables.