Transparent ruler – like in the good ol’ days [Bioanalytics]

posted by ElMaestro  – Belgium?, 2018-11-05 22:43 (758 d 10:02 ago) – Posting: # 19536
Views: 5,029

Hi Ohlbe and Hötzi,

Thanks for your qualified opinions.

I am inclined to do this:

lines(c(5.6, 5.6), c(4.1,18), col="green", lwd=6)
lines(c(8, 8), c(4.1,8.8 ), col="red", lwd=6)


where the red line indicates the level of noise (in this case, right of the peak) and the greeen one is the signal. Roughly.

Note that in both cases I quantify s as well as n in one direction from the baseline mean or median or whatever.

Thus I am landing at s:n = (18-4.1) / (8-4.1) = 3.6.
I am not in any way claiming this is better or worse, only that this is my idea of an approach.

If I recall correctly, if you are "a large software vendor" -and I will mention none in particular- you can also do something like:

k=3                   #a miserable sad pointless constant to make s:n look better ??
a=sd (y3[400:714])    #sd of points on the peak
b=sd (y3[800:1000])   #sd of points adjacent to the peak
sn=k*a/b


which gives a result of about 5.:-D
Personally, I would of course always adjust k so that s:n is not less than 10 or so, just to avoid questions. I mean, I care about my data because I am not a nasty person :-D:-D:-D

I could be wrong, but...

Best regards,
ElMaestro

No, of course you do not need to audit your CRO if it was inspected in 1968 by the agency of Crabongostan.

Complete thread:

Activity
 Admin contact
21,232 posts in 4,427 threads, 1,482 registered users;
online 7 (1 registered, 6 guests [including 4 identified bots]).
Forum time: Thursday 08:45 CET (Europe/Vienna)

Every man is fully satisfied that there is such a thing as truth,
or he would not ask any question.    Charles Sanders Peirce

The Bioequivalence and Bioavailability Forum is hosted by
BEBAC Ing. Helmut Schütz
HTML5