Experimental design is just a t-test? At least accord to that picture it seems that way. There are no ANOVA or interaction test?
Do websites usually just use t-test only? Like adding one feature at a time?
Do websites usually just use t-test only? Like adding one feature at a time?
Are you talking about more than one experimental design in terms of comparing the exp/control distributions or something else?
> your t-test results should then be valid if the two features are independent.
Assuming that your assumption are correct on interaction effect.
You can do a hypothesis test on that assumption while including both factors (the two features). Which will clear away any doubt with a 95% confidence or hire a statistician =).