# Morris High School has introduced a policy designed to improve the working conditions of its new teachers. As a resul...

IkeHansen on May 13, 2021

Explanation of why D is correct

I'm having difficulty understanding why the correct answer is right and why the incorrect answers are wrong. Just confused mainly by the "new" teachers and "all" teachers transition.

Victoria on May 13, 2021

Hi @IkeHansen,

Happy to help!

We learn that Morris High School has introduced a policy to improve the working conditions for its new teachers.

We learn that this policy has affected the proportion of teachers who quit during their first year. 1/4 of part-time teachers quit during their first year as compared to 1/3 of full-time teachers. Therefore, we are not transitioning from new teachers to all teachers because we are still focused on those who are in their first year of teaching (i.e. new teachers).

The author concludes that more full-time teachers at Morris quit during their first year than part-time teachers.

What is the flaw here? The author uses a proportion to draw a conclusion about the absolute number.

If there is an equal number of part-time and full-time teachers, then this conclusion can be properly drawn. However, what if there are more part-time teachers than full-time teachers?

Let's say there are 16 part-time teachers and 9 full-time teachers. If this is the case, then 4 part-time teachers quit in their first year as compared to 3 full-time teachers. Therefore, the author overlooks the possibility that Morris employs more new part-time teachers than new full-time teachers. This is restated by answer choice (D), making it our correct answer.

Answer choices (A) and (B) are incorrect for the same reason. We are not focused on the change in the proportion of new teachers who quit. The author draws a conclusion about the total number of full- and part-time teachers who now quit during their first year.

Answer choice (C) is incorrect because it supports the author's conclusion. If there are more full-time teachers than part-time teachers and a greater proportion of full-time teachers quit, then we can conclude that more full-time teachers quit than part-time teachers.

Answer choice (E) is incorrect for the same reason as answer choice (C). If the number of part-time and full-time teachers is the same, then the fact that a greater proportion of full-time teachers quit means that the author's conclusion is correct.

Hope this helps! Please let us know if you have any further questions.