The error here is that we are given the percentage of new part-time and full-time teachers that are quitting during their first year, but not actual numbers. We don't know how many teachers quit, we only know what percentage quit.
For example, if there were 100 part-time teachers and only 30 full-time teachers, this would mean that 25 part-time teachers have quit, but only 10 full-time teachers have quit. Therefore, in this case, it is not true that that more full-time teachers than part-time teachers have quit.
(A) is incorrect because we do not care about what was happening "before the new policy." The conclusion is that "more full-time than part-time teachers at Morris NOW quit during their first year." Therefore, answer choice (A) is irrelevant.
(B) is incorrect because it is too vague. Depending on what that "same number" is, seeing as how we do not know any specific number of how many new teachers are quitting during their first year, it could be true that "more full-time teachers than part-time teachers have quit," but it also doesn't have to be true. There's still too much missing information.
(C) is incorrect because this information strengthens the stimulus rather than making it questionable. If there are more new full-time teachers than part-time and a higher percentage of full-time teachers quit during their first year, then it must be true that more full-time than part-time teachers are quitting during their first year.
(D) is CORRECT because it clearly discusses the flaw in the stimulus. If there are more new part-time teachers than new full-time teachers, then it doesn't have to be the case that "more full-time than part-time teachers at Morris now quit during their first year." Always be weary when you see ratios or percentages in a stimulus without any actual numbers.
(E) is incorrect because this information strengthens the stimulus rather than making it questionable. If there are equal numbers of new part-time and full-time teachers, and a higher percentage of full-time teachers quit during their first year, then it must be true that more full-time than part-time teachers are quitting during their first year.
Hope that helps! Let me know if you have any other questions!
MattJanuary 15, 2015
I picked D and could not see why it was wrong. FYI: E is shown as correct on the answer sheet.
NazJanuary 15, 2015
Sorry for the confusion. We fixed the issue in the Welcome Packet. The correct answer is, indeed, (D).
