Hi to all
is there any meaningful analysis for the following data:
a: 62 57 230

b: 10587 5721 3550

we have only three pairs of data and everybody can realize that "a" is
increasing and "b" is decreasing. But is there any statistical function
for such a small sample size to get any "p-value" (for the journals...)

Well you could do an ANCOVA, and the p-value for the slope being

Knut Krueger wrote:
Hi to all
is there any meaningful analysis for the following data:
a: 62 57 230

b: 10587 5721 3550

we have only three pairs of data and everybody can realize that "a" is
increasing and "b" is decreasing. But is there any statistical function
for such a small sample size to get any "p-value" (for the journals...)

Well you could do an ANCOVA, and the p-value for the slope being different
is just under 0.05. But quite frankly, I would tell the journal to sod
off if they insist on p-values, and suggest that the editors learn to use
their common sense (hmm, I might not express it in quite those terms,
though). Just be clear that any test is not justified, because of the
small sample size.

The P value for the difference in slopes isn't significant if you log
transform the data first, which I suspect would be a sensible thing to do
given the way the data look. But of course you can't know whether it is or
not from that sample size, unless you know whether the outcome variable is
generally known to be normally or log-normally distributed.
We expect log normally (further research may be show that) but OO and

I'm not sure I agree that everyone can realise that "a" is increasing and
"b" is decreasing. Probably, yes, but how do you know the fourth value in
the series would continue the trend?

I totally agree, however, about telling the journal editor to sod off and
get some common sense (again, ideally phrased in a more diplomatic manner).

Adam schrieb:

The P value for the difference in slopes isn't significant if you log
transform the data first, which I suspect would be a sensible thing to
do given the way the data look. But of course you can't know whether
it is or not from that sample size, unless you know whether the
outcome variable is generally known to be normally or log-normally
distributed.
We expect log normally (further research may be show that) but OO and
zero will never be reached for a.
means a will not decrease below a steady state, even b is growing up
maybe over 100.000 and minimizing b f.e below 50 will destroy the
experimental setup

I'm not sure I agree that everyone can realise that "a" is increasing
and "b" is decreasing. Probably, yes, but how do you know the fourth
value in the series would continue the trend?

isn't this always the problem if there are only three points?
Couldn't you find a lot of fitting functions like sin cos tan and much
other into three points ...

I totally agree, however, about telling the journal editor to sod off
and get some common sense (again, ideally phrased in a more diplomatic
manner).

I am afraid a p-value form a not fitting statistical model is more
accepted than any proper illustration ...

From the "it's enough to make you weep" department.