They break out contributions by OS, which is kinda neat to see. Admittedly an outlier could move the needle if they really want to throw some money down.
~4k individual purchases.
Average contribution:
Windows $5.48 Mac $7.09 Linux $11.45
~4k individual purchases.
Average contribution:
Windows $5.48 Mac $7.09 Linux $11.45
So, a few Linux users donating $500 could sway an identical distribution to the Mac or Windows users.
total revenue: $301,252.18
number of purchases: 43,819
average purchase: $6.87
average windows: $5.72
average mac: $7.72
average linux: $13.72
windows: ~54% , or ~$162,676.18
mac: ~23% , or ~$69,288
linux: ~23% , or ~$69,288
Now, it's true that a very large contribution could influence the mean. However, they also include a list of the top 10 contributions:
top 10 contributions:
$1,000
$700
$666
$650
$600
$500
$500
$337.42
$313.37
$300
outlier revenue: $5,566.79
adjusted total revenue: $295,685.39
adjusted linux revenue: ~$63,721.21
adjusted linux average: $12.61
You could argue that a sufficient number of Linux users donating in the $100-$300 range could skew the results, but I believe such a high number of extremely generous users would prove my point anyway.
Average Windows: $5.69
Average Mac: $7.69
Average Linux: $14.17
As a Linux user, yes I am grateful! :) It isn't about attempting to demonstrate that Linux is better than Windows or Mac, but supporting the developers and making others realize that Linux can be good for gaming too.