Not sure if this is the right place to ask, but I'll try:
What's the right way to calculate the average open rate of mails:
- simple average?
- average of averages?
For example, if we have:
- First mail, that was sent to 100 contacts, and opened by 10 contacts
- Second mail, that was sent to 1000 contacts, and opened by 500 contacts
We get:
- simple average: $\frac{10+500}{100+1000} = 0.46$
- average of averages: $\frac{ \frac{10}{100} + \frac{500}{1000}}{2} = 0.3 $
Is there a "right" answer, or is it depends on something?