Mrs. Orlof teaches two history classes, one in the morning and one in the afternoon. Yesterday she gave the same test to both classes. Anyone who failed the test must take a retest. Since a greater percentage of students who took the morning test failed the test than students who took the afternoon test, more of Orlof’s morning history students than afternoon history students will have to take the retest.
The conclusion above is not necessarily valid because
a) more students in the morning class may have passed the test than failed the test
b) some students may have been absent from both classes
c) some of the students who passed the afternoon test may have received information about the test from morning students
d) more students may have taken the test in the afternoon than in the morning
What do you think?
Please check your answer choices. I think there's an error in one or more of them.
The answer is c) some of the students who passed the afternoon test may have received information about the test from morning students. This could potentially affect the validity of the conclusion because if the afternoon students received information about the test from the morning students, it could have influenced their performance and could mean that the percentage of students who failed the test in the morning class is not entirely accurate. Therefore, the conclusion cannot be solely based on the percentage of students who failed the test in each class.
To determine the validity of the conclusion, let's evaluate each option:
a) If more students in the morning class passed the test than failed the test, it would undermine the conclusion that more morning students will have to take the retest. Therefore, this option supports the conclusion.
b) If some students were absent from both classes, it means they did not take the test. As such, they cannot be categorized as either passing or failing. This option could potentially undermine the conclusion, as it suggests that there might be fewer students overall who would need to take the retest. However, it does not directly address the comparison between the percentages of students who failed each class.
c) This option suggests that some students in the afternoon class may have gained an advantage by receiving information about the test from morning students. While this scenario may impact the fairness of the results, it does not address the comparison between the percentages of students who failed each class. Therefore, it does not invalidate the conclusion.
d) If more students took the test in the afternoon than in the morning, it could potentially lead to a higher number of afternoon students who need to take the retest. This scenario, like option a, would undermine the conclusion. Therefore, this option supports the conclusion.
From the analysis above, the invalidity of the conclusion is best supported by option a) more students in the morning class may have passed the test than failed the test.