Here is a mathematical formula that acts as a test of clinical significance. This formula helps clinicians determine the clinical value of a research study. When does a patient’s test more likely than not indicate they fall in the normal population? When does he test more likely than not indicate they fall in the abnormal population?
The mean value for the normal population = Xn
The standard deviation for Xn = SDn
The mean value for the abnormal (sick) population = Xa
The standard deviation for Xa = SDa
STEP 1. Calculate the threshold Z value:
Z = (Xa – Xn) / (SDa + SDn)
STEP 2. Calculate the threshold value:
Threshold = Xa – (Z * SDa)
When Xa > Xb, when the patient’s test value is greater than the threshold value, then it is more likely than not that they fall in the abnormal population. When the patient’s test value is less than the threshold value, then it is more likely than not that they fall in the normal population.
I’m crossing over the lines
that lead on to you,
ever along my way.
And it is you that draws me
the lines I move.
Going along, being sure the way
will lead us on down the road that together we know.
One step further, one time again and when
we see together forever it sends
us further along the way.
So I cross the lines
that lead on to you
over to you.
And I cross the lines
that lead on to you
over to you.
So now today we find
that its time again
to go over the path anew.
And it’s you that draws me in as I move
goin’ along, makin’ sure the way.
The love we hold on together, forever it sends us
One step onward, feel the truth that goes
Straight from my heart right to you and then
we go further along the way.
So I cross the lines
that lead on to you
over to you.
And I cross the lines
that lead on to you
over to you.
Over and over and
on and on
over to you.
It goes
over and over and
on and on
over and over and
on and on it goes
over and over and
on and on it goes
over and over
and on and on.
- Tom Heston
Lake Washington and the Olympic Mountains are in the background.
