I feel like this is the silliest question ever, so I apologize in advance!

a statement reads:

Z is the difference between X and Y.

Which of these is true?

  • Z = X - Y
  • Z = Y - X
  • Z = |X - Y|

I want to say it's the third, or whichever is larger minus whichever is smaller, but I can't be certain.

This came up in a textbook I'm studying. Attrition is the difference between the actual number of guest rooms picked up and the number of guest rooms guaranteed by the meeting sponsor in the contract.


(note: I have no idea how to tag this question, so if someone can help, that'd be appreciated. :) )


You're correct: given no context, then "the difference $Z$ between $X$ and $ Y$ is given by $$Z = |X-Y|$$

This would be the "absolute" difference, which is appropriate here, as we are asked simply for representing the difference between $X$ and $Y$: this way, the difference is independent of which is larger $X$ or $Y$.

However, in your problem statement, if you know $X$ represents actual number...and $Y$ represents guaranteed number, then attrition $A$, if I understand your definition correctly, would be $$A = X - Y$$

  • $\begingroup$ Sounds reasonable to me! +1 $\endgroup$ – Amzoti May 8 '13 at 0:42
  • $\begingroup$ And to me also. :-) $\endgroup$ – mrs May 8 '13 at 3:59
  • $\begingroup$ Hello, dear friend! Not having a good night (for me). I hope it's good morning for you!! ;-) $\endgroup$ – Namaste May 8 '13 at 4:03
  • $\begingroup$ I saw that. What is really this measurable thing circulating us? I don't understand. @amWhy $\endgroup$ – mrs May 8 '13 at 4:30
  • $\begingroup$ @Babak Who knows??? A mystery, my friend ;-) $\endgroup$ – Namaste May 8 '13 at 4:35

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.