On 5/19/2022 8:43 AM, Kim Elmore wrote:
My test worked, so I'll try again...
To everyone that has commented: Thank you very much! This discussion
is fabulous!
I concede the point that statistically, there is likely to be score
improvements with 1 dB power increase and certainly 2 dB. These are
best described as statistical improvements and I suspect that the data
set has to be moderately large to detect a "significant" difference,
that is for a statistic to have much power. Thus a DXer, who is not a
contester (there are such things) probably won't notice a significant
improvement in how long it takes to break through a pile-up with a
power increase of 1 dB. Over a long run, a contester will be able to
see a score increase at with a 1 dB power increase. A smaller data
set (possibly much smaller) will show statistical score improvements
given a 2 dB increase, significant at some arbitrary p-value.
Perhaps this is what you are getting at, Kim, but unless an operator is
switching between power levels on some fairly short time interval, so as
to create two otherwise identical data sets, I don't see how you can get
any meaningful statistics when looking at small differences in power.
Comparing previous contests or within a single contest against another
nearby station running a slightly different power still leaves you with
a lot of uncontrolled variables.
I tend to skepticism when someone says they can notice a significant
improvement given a *single* contest assuming everything else
(including the operator) is held constant. It will take several
contests to see a *statistical* improvement but I'll now bet it's
there. Fewer contests will be required for a 2 dB increase. I prefer
resampling (i.e. a permutation test) to parametric statistics simply
because parametric test assumptions are almost always violated,
leading to unknown degradations of the test's validity.
You could test this hypothesis by taking some public logs and dividing
them in two by making one log out of even minute entries and another log
out of odd minute entries and comparing the scores (QSOs, QSO points,
mults, total score, etc). That would give you some feel for how
sensitive a test would be that interleaved Pout vs Pout + NdB with
similar dwell intervals. If the score difference between odd and even
minutes in the control logs (i.e. constant power logs) was consistently
less than 10%, then the power difference in the interleaved power
difference logs would have to show a score difference significantly
greater than 10% to be considered statistically significant.
73, Mike W4EF
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|