[ELI5] Why average of 12 months growth percentile is not the same as sum of growth percetnile?


Jan 2022 sales 100
Jan 2021 sales 50

Feb 2022 sales 150
Feb 2021 sales 90

Jan sales growth is 100%
Feb sales growth is 67%
Average growth **83%**

2022 sales total 250
2021 sales total 140
Percent growth is **79%**

Why do i feel stupid, ama grown ass man and i cnt figure it out

In: 0

You might be talking about the Simpson’s Paradox – the average of some averages is not the average -> https://lemire.me/blog/2005/10/28/average-of-averages-is-not-the-average/

Aside from the answers that were already given, you’re probably looking for the term *percentages* rather than *percentiles*.

They’re very different things — percentiles are about ranking values on a cumulative scale of 100. For example, a student taking a math quiz can be said to have a 98th-percentile score when their score is higher than 98% of other scores they’re being compared with. The 50th percentile is also/better known as the median.

Hope this helps get you less confusing search results.

Average = SUM / COUNT.

That is, you add the items you want to average, then divide by the total number of items.

The average of 100 and 67 is 83.5, because that’s 167/2.


Percent change is DIFFERENCE / ORIGINAL.

When they calculated the percent growth, they did 250-140 = 110, that’s the “difference” for the numerator.

The “original” number is 140, because 2021 is before 2022.

So we do 110/140 = 0.786