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# Percentage change in mass watch

1. Why use percentage change in mass rather than just change in mass?
2. sometimes it's because the two things have different masses to begin with and so it's much more reliable therefore to give the change as a % change of what it was therefore allowing for better comparisons. so % change will show you the size of the change relative to it's original mass. Here is a simple example:
2 people lose weight.
Person A started at 160lbs and went to 140lbs.
Person B started at 130lbs and went to 110lbs.
If you are just comparing the differences in mass then they both lost 20lbs so it looks the same. however when you use the % change you can see that the %change for person A is 160-140/160×100 = 12.5%
The %change person B is 130-110/130×100 = 15.4%.
comparing these you can see that person B has lost a greater % of their body weight than person A and so while they both lost 20lbs, you must use %change to find out how great a loss this was relative to their starting weight.
3. (Original post by Puppo)
sometimes it's because the two things have different masses to begin with and so it's much more reliable therefore to give the change as a % change of what it was therefore allowing for better comparisons. so % change will show you the size of the change relative to it's original mass. Here is a simple example:
2 people lose weight.
Person A started at 160lbs and went to 140lbs.
Person B started at 130lbs and went to 110lbs.
If you are just comparing the differences in mass then they both lost 20lbs so it looks the same. however when you use the % change you can see that the %change for person A is 160-140/160×100 = 12.5%
The %change person B is 130-110/130×100 = 15.4%.
comparing these you can see that person B has lost a greater % of their body weight than person A and so while they both lost 20lbs, you must use %change to find out how great a loss this was relative to their starting weight.
Thank you, I really appreciate the example as well.

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Updated: October 19, 2017
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