I have two sets of numbers like this
a = [400, 2934, 450, 675]
b = [700, 314, 9433, 579]
I need to calculate the percentage difference of their averages. The goal is to be able to say set b has improved or deteriorate by a certain percentage in average. I am using the percentage difference formula as this:
(|ΔV|)/((ΣV)/nV))*100
Meaning if I have only 400 and 700 I would have this:
(|400-700|)/((400+700)/2)*100 = 54.5455%
However, I have no idea how to get the percentage difference of their averages. I searched online and read many articles but couldn't find an answer. Can anyone help me with this? Thanks.
Percent Difference is defined as $$\% \text{ Difference}=\dfrac{\lvert\,X_{acc}-X_{exp}\,\rvert}{X_{acc}}*100.$$ Where $X_{acc}$ is an accepted value and $X_{exp}$ is an experimental value measured quantitatively. We may adapt this formula for our needs accordingly.
Therefore, if you are choosing a certain average, say $700$ as the average to compare to $400$, you would have $$\% \text{ Difference}=\dfrac{\lvert\,700-400\,\rvert}{700}*100=42.857\%.$$ Therefore, the average $400$ is $42.857\%$ different from your average $700.$
As pointed out in a comment by David K., you can say there was a drop in $42.857\%$ from $700$ to $400$, or just a $-42.857\%$ difference from $700$ to $400$.