It seems to me that if they used two independent labs, splitting the samples
at time of collection, this could eliminate a lot of doubt.

Montesquiou wrote in message
...

a icrit dans le message de news:
...

Montesquiou wrote:
"CowPunk" a icrit dans le message de news:
...
1% of 12000 = 120

120:380 ~ 1:3


Oh my friend !!!

With all due respect if it is way they teach statistic in your country
...
You are lost.

However as I have many friends in the USA and I know they are not so
ignorants in Math, I believe the problem is your.

Since your original post you DECIDED that 1% of the test were wrong.

So 1% of the 380 positive (that you DECIDED BY YOUR OWN) are wrong.

1% of 380 is 3.8.

Turn your problem the way you want 1% is allway 1% and NEVER 1:3 (33.33
%)
!!

Oh my God, pls help me !

I am here and I will help you.

First, in each test there is an A and B sample and the test is done on
each. So if the there is a 1% chance of error on any give sample,
then the probablitity or an error both is found be multiplying .01
times .01 or .0001 or 0.01%.

Second, do not assume any error percentage until one appears in the
scientific literature, that is one that has been established with a
proven protocol and by actual perfroming many blind tests with samples
of known quality. One of the difficulties in this area is that test
error rates have not been established and made publicly available.

***

Correct.

It was so difficult for me to explain to him his wrong mathematical
reasoning that I did not even argued on the wrong initial suppositions he
did.