[lupire]

You are confusing confidence intervals (used to say that you are confident the increase is positive at all) with error margin (the false precision in the 3rd significant figure).

[tdmckinlay]

You are right, my bad! Thanks for catching that in the comment above, I've updated it

[vntok]

That does not bode well for the rest of the methodology...

[boomboomsubban]

Mixing up terms in casual conversation happens to everyone, and is not a sign of a meaningful problem.

[johnsmith4739]

I don't know why people downvote you:

//> we finally have an absolute number of sales measured, but no way of knowing - representing all sales within a period or just cherry picked?

//> for the rest of the population, did it reduced sales?

//> was there any randomised test or not, because in the latter case there could be other biases we're unaware of

//> the increase is compared to what exactly?

//> any WHY is purely speculative as what was measured was WHAT people did. Internal motivation is in this case unproven, there is just a potential correlation.

//> confuses me to hell people taking about error margins and confidence intervals for something measured directly.