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Author Topic: computing 1-p_value in Weight by Chi Squared Statistic operator  (Read 6404 times)
haddock
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« Reply #15 on: November 20, 2012, 04:25:56 PM »

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Fallacy: 1-P is the probability that the alternative hypothesis is true
->
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computing 1-p_value in Weight by Chi Squared Statistic operator
is dangerous for those that do not understand what they read.
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Where is the wisdom we have lost in knowledge?
Where is the knowledge we have lost in information?

T.S.Eliot ~ Choruses from the Rock 1934
dan_
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« Reply #16 on: November 20, 2012, 04:36:08 PM »


Haddock, thanks for finally expressing yourself.

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1-P is the probability that the alternative hypothesis is true

Smiley I did not make such a statement. This is basic thing. Read my posts again. Wink

And perhaps read at least one introductory book from those I recommended you above, unless
you already did so (in which case I am so curios why you do not want to tell
us about it). This may help you find out about and understand concepts used in the content of the current topic.
« Last Edit: November 20, 2012, 07:32:18 PM by dan_ » Logged
haddock
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« Reply #17 on: November 20, 2012, 08:53:47 PM »

Go Dan, go! If you shout someone might listen...
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Where is the wisdom we have lost in knowledge?
Where is the knowledge we have lost in information?

T.S.Eliot ~ Choruses from the Rock 1934
dan_
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« Reply #18 on: November 21, 2012, 06:43:32 PM »

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Go Dan, go! If you shout someone might listen...

 Cheesy  Haddock, it seems you have run out of Data Mining arguments! Smiley

It does not surprise me since I know you need to improve fundamentally
your expertise in this area before you are able to talk in depth about such topics.
OK, your many stars show you are good at playing  with RapidMiner (you are
good at clicking on buttons I think), but your comments show you lack fundamental knowledge in Data Mining.

With no degree in Computer Science (I bet) and no book read out of a "must-read" list
of Data Mining books, you seem to be a fake Data Mining "guru" on this forum,
behaving badly on quite many occasions with new comers. So I reiterate my advice: read at least
one serious Data Mining book and after that come back and criticise users here.

Next lesson for you will follow shortly here http://rapid-i.com/rapidforum/index.php/topic,5823.0.html 

Dan
« Last Edit: November 21, 2012, 06:59:24 PM by dan_ » Logged
haddock
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« Reply #19 on: November 21, 2012, 08:05:00 PM »


I went on a RapidMiner course, I take it you think that was rubbish as well.

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Where is the wisdom we have lost in knowledge?
Where is the knowledge we have lost in information?

T.S.Eliot ~ Choruses from the Rock 1934
wessel
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« Reply #20 on: November 22, 2012, 01:43:24 AM »

Both of you apply the same argument:
"Its true what I'm saying because the other guy knows nothing and I know all".

Would be nice if you could make all future posts on topic and interesting to read.

Best regards,

Wessel
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haddock
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« Reply #21 on: November 22, 2012, 09:51:06 AM »

Wessel,

Please read my very first post in this miserable thread - I pointed out that Wikipedia said this approach had dangers, ever since then this **** has banged on about how little I know. That's absolutely irrelevant, It doesn't address what is written in Wikipedia, and it reflects very badly on RM that nobody else flags up the 1-P fallacies. Please read your comment again - is it on point, or are you just being pompous?
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Where is the wisdom we have lost in knowledge?
Where is the knowledge we have lost in information?

T.S.Eliot ~ Choruses from the Rock 1934
Marco Boeck
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« Reply #22 on: November 22, 2012, 01:58:40 PM »

Hi,

@dan_, haddock:
I've watched your personal feude now for some time in the hopes you two would calm yourself down and refrain from using personal insults and provocations. Sadly this did not happen so I guess I have to make this very clear: This forum is for people to talk about Rapid-I products and help each other out when questions arise. It is NOT a place for insults, slander, arrogance and other nonsense. Nobody is required to like everybody but everybody is required to behave and control himself. Future open and hidden insults or provocations by either side will not be tolerated.

Regards,
Marco
« Last Edit: November 22, 2012, 02:03:15 PM by Marco Boeck » Logged

dan_
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« Reply #23 on: November 22, 2012, 08:51:15 PM »

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it reflects very badly on RM that nobody else flags up the 1-P fallacies

Haddock is right that there are such fallacies concerning the p-values. Some appearing even in RapidMiner. For instance look at the  T-test operator:

Quote
This operator uses a simple (pairwise) t-test to determine the probability that the null hypothesis is wrong


BTW this type of fallacy may discourage many R users that do Data Mining in R, to use also RapidMiner.  Why? Because using stats fallacies in a software's documentation gives a taste of unprofessional.  The R users usually have a good level of statistical literacy and observe easily these fallacies. I suggested this aspect (regarding some wrong use of statistical language & concepts in RapidMiner) to be corrected http://rapid-i.com/rapidforum/index.php/topic,5823.0.html

The probability computed by the t-test mentioned above (the so called p-value) is not the probability that the null hypothesis is right or wrong.
According to [Ross,  Introductory Statistics, Academic Press, 2010] or any other Stats book the p-value is the probability for the test statistic to be beyond some values (computed using the data sample), assuming the null hypothesis was true. When the test statistic is in the critical region (or equivalently, the p-value is below a threshold called significance level), the null hypothesis is rejected as it is judged to be inconsistent with the data sample.

There is another fallacy in which the expression 1-p appears, where p is a pvalue. Since the expression 1-p appears also in my posts,
Haddock made a wrong/superficial connection between this fallacy and the idea that I had exposed in this topic. It's wrong to put the
label "fallacy" whenever one sees 1-p (just because there exists some fallacy about 1-p). Such confusions are possible when statistical inference and tests are not sufficiently understood (although statistical tests are used in Data Mining - for instance in decision tree algorithms like CHAID and QUEST, etc). My backgrounds in Computer Science and Mathematical Statistics help me to avoid such fallacies: I did not state in my posts that 1-p is the probability that the alternative hypothesis is true, as Haddock suggested. This kind of error is certainly not made by statisticians.

@Haddock I am ready any time to discuss on data mining with you. It is regrettable however that you use such a language when you run out of
data mining arguments. It's good though that you attended a RapidMiner course. Obviously it is hard to make such brief courses comprehensive. If you want more, get one of the books I recommended in the list. In particular this will demonstrate you also how p-values are used in Data Mining.
« Last Edit: November 23, 2012, 04:09:34 PM by dan_ » Logged
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