Here is what the author had to say...
There's a little more to this than meets the eye.
Conventionally, most authors call Type I errors false negative, and
Type II false positive; but I do see some authors who define them the
other way round.
I think the reason for this is that in hypothesis testing, we are
strictly speaking testing the null hypothesis, ie. the hypothesis that
there is no difference, and when we reach a positive conclusion about
the null hypothesis, we are reaching a negative conclusion about the
phenomenon we are studying.
For example, let's say we are testing a drug vs. a placebo.
Let's say that we find that there is no difference between the drug and
the placebo; the null hypothesis is that there is no difference, so we
accept the null hypothesis.
If in reality this is a mistake, we have made a false positive (type
II) error (we have reached a positive conclusion, but it is a false
one).
But some authors would say that a study which reaches a conclusion that
there IS a significant difference is a "positive" study, and one that
concludes that there is no difference (eg. between a drug and a
placebo) is a "negative" study. (This sounds like common sense, but you
have to remember that strictly speaking in statistics we are testing a
null hypothesis, not a drug).
An example of this is shown on the American College of Physicians
online primer at
http://www.acponline.org/journals/ecp/novdec01/primer_errors.htm (and
the table it is linked to)
where they say "A type I error is analogous to a false-positive result
during diagnostic testing: A difference is shown when in "truth" there
is none." - but this is only because they are taking the "common sense"
idea that a "positive" result is one that shows a "difference"
- and if you look at the table which the page links to, you see that a
type I error is one where you conclude there is no "difference" when in
fact there is one; which is the same as I am saying, except they
confuse us by referring this to a "positive" study!
It sure is confusing. But basically everyone agrees that a type I is
rejecting the null hypothesis when it is true, and a type II is
accepting a null hypothesis that is false; the "false positive" or
"false negative" terminology really depends on whether you are
referring to the null hypothesis or the alternative hypothesis.