If you've ever gotten an asthma test, they'll measure your FEV.
Well, you would be skeptical.
I mean, there's very little basis for a biological relationship there.
Breath mints are just sugar.
It doesn't seem reasonable that they would impact lung function.
But maybe, but what you've really be thinking is,
well, what other variables might be explaining this relationship?
And you might come up with two hypotheses.
One is, this person dug through lots and lots and lots of variables and
just found the one that was significant, and it's just a chance of association.
And that's the problem of multiplicity.
Okay, so we'll talk about that in other aspects of this course in the inference
course, but let's just assume that this person didn't do that, they looked only
at a couple of variables, and the multiplicity concerns weren't so bad.
Then what would you think?
Well, likely, you would think,
well, probably the real problem is smokers tend to use more breath mints, and
smoking has this long relationship with lung function, so
it's well-established that chronic exposure to a smoker,
even second-hand smoke has negative impacts on lung function.
So it's probably that, it probably has nothing to do with the breath mints,
it's a indirect effect of breath mints through smoking,
not a direct effect of breath mints on lung function.
That would be your likely hypothesis.