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Science Forum Index » Statistics - Math Forum » Jarque-Bera test: confidence intervals for normal data
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| Luis A. Afonso |
Posted: Wed Mar 07, 2007 6:16 am |
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Jarque-Bera test: confidence intervals for normal data
Taking in consideration that the J-B Test (1980) involves simultaneously the Skewness and Kurtosis of samples one thinks that is superior to the Skewness coefficient in the job to find if Populations are normal.(see Wikipedia under Jarque-Bera test)..
Asymptotically the critical values are those of the Chi-squared Distribution, 2 degrees of freedom. All researchers are unanimous to state that this convergence is very slow and, consequently, the approach is poor for short sample sizes, N. (see Steve Lawford (2004), Finite-Sample quantiles of the Jarque-Bera test).
For the 5% and 1% levels of significance the asymptotic critical values are respectively 5.991 and 9.210. However reading on the S. Lawford´s graphics we get 5.5 (approx.) for 5% L.S., N=100. Even for N=500 that value is not attained.
The job is to find, by Monte Carlo, like the Lawford´s work, same correct critical values of this test.
I´m following strictly the algorithm as it is displayed in Wikipedia.
________licas (Luis A. Afonso) |
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| Luis A. Afonso |
Posted: Wed Mar 07, 2007 12:55 pm |
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Jarque-Bera test: confidence intervals for normal data, 2
RAW RESULTS
_SIZE_________5%___________1%______
__10______2.54__2.53_____5.72___5.70__
__15______3.30__3.29_____8.26___8.18__
__20______3.81__3.79_____9.73___9.66__
__25______4.16__4.16____10.78__10.74__
__30______4.40__4.41____11.33__11.27__
__35______4.57__4.59____11.67__11.80__
__40______4.74__4.77____11.95__12.01__
__45______4.86__4.88____12.29__12.19__
__50______4.95__4.95____12.36__12.46__
(1 million of samples, size N, 2 times, for each sample size). Remembering that the theoretical, asymptotical, Chi-squared, 2 DF, are 5.991 (5%) and 9.210 (1%) this calculation’s utility seems unquestionable.
________licas (Luis A. Afonso) |
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| Jack Tomsky |
Posted: Wed Mar 07, 2007 2:04 pm |
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Quote: Jarque-Bera test: confidence intervals for normal
data, 2
These are not confidence intervals.
Jack
Quote: RAW RESULTS
_SIZE_________5%___________1%______
__10______2.54__2.53_____5.72___5.70__
__15______3.30__3.29_____8.26___8.18__
__20______3.81__3.79_____9.73___9.66__
__25______4.16__4.16____10.78__10.74__
__30______4.40__4.41____11.33__11.27__
__35______4.57__4.59____11.67__11.80__
__40______4.74__4.77____11.95__12.01__
__45______4.86__4.88____12.29__12.19__
__50______4.95__4.95____12.36__12.46__
(1 million of samples, size N, 2 times, for each
sample size). Remembering that the theoretical,
asymptotical, Chi-squared, 2 DF, are 5.991 (5%) and
9.210 (1%) this calculation’s utility seems
unquestionable.
________licas (Luis A. Afonso) |
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| Luis A. Afonso |
Posted: Wed Mar 07, 2007 2:42 pm |
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Jarque-Bera test: confidence intervals for normal data, 3
Jack L. Tomsky KNOWS NOTHING about it is saying.
_____licas (Luis A. Afonso) |
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| Jack Tomsky |
Posted: Wed Mar 07, 2007 2:50 pm |
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Quote: Jarque-Bera test: confidence intervals for normal
data, 3
Jack L. Tomsky KNOWS NOTHING about it is saying.
_____licas (Luis A. Afonso)
Well, what is the parameter for which you obtained your confidence intervals?
Jack |
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| Luis A. Afonso |
Posted: Wed Mar 07, 2007 3:32 pm |
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Jarque-Bera test: confidence intervals for normal data, 3
After *smoothing*
__V.C.__5% Significance
__10__2.54____11__2.71__
__12__2.87____13__3.02__
__14__3.16____15__3.29__
__16__3.41____17__3.52__
__18__3.62____19__3.72__
__20__3.81____21__3.89__
__22__3.96____23__4.03__
__24__4.09____25__4.15__
__26__4.21____27__4.26__
__28__4.31____29__4.36__
__30__4.40____31__4.44__
__32__4.48____33__4.52__
__34__4.56____35__4.59__
__36__4.62____37__4.66__
__38__4.69____39__4.72__
__40__4.74____41__4.77__
__42__4.80____43__4.82__
__44__4.85____45__4.87__
__46__4.89____47__4.91__
__48__4.92____49__4.94__
__50__4.95_____________
For example H0 is not rejected (at 5% significance level) if a sample of size 50 has a JB equal or less than 4.95.
________licas (Luis A. Afonso) |
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| Jack Tomsky |
Posted: Wed Mar 07, 2007 4:02 pm |
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Quote: Jarque-Bera test: confidence intervals for normal
data, 3
After *smoothing*
__V.C.__5% Significance
__10__2.54____11__2.71__
__12__2.87____13__3.02__
__14__3.16____15__3.29__
__16__3.41____17__3.52__
__18__3.62____19__3.72__
__20__3.81____21__3.89__
__22__3.96____23__4.03__
__24__4.09____25__4.15__
__26__4.21____27__4.26__
__28__4.31____29__4.36__
__30__4.40____31__4.44__
__32__4.48____33__4.52__
__34__4.56____35__4.59__
__36__4.62____37__4.66__
__38__4.69____39__4.72__
__40__4.74____41__4.77__
__42__4.80____43__4.82__
__44__4.85____45__4.87__
__46__4.89____47__4.91__
__48__4.92____49__4.94__
__50__4.95_____________
For example H0 is not rejected (at 5% significance
level) if a sample of size 50 has a JB equal or less
than 4.95.
________licas (Luis A. Afonso)
What you've described is a statistical test for the composite hypothesis of normality. But what is the parameter that the confidence interval pertains to?
In other words, given a sample of size N, what is your unknown parameter and what is your confidence interval? That's what we were promised by your thread title.
Jack |
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| Luis A. Afonso |
Posted: Thu Mar 08, 2007 10:42 am |
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Jack Tomsky wrote
*** What you've described is a statistical test for the composite hypothesis of normality. But what is the parameter that the confidence interval pertains to? In other words, given a sample of size N, what is your unknown parameter and what is your confidence interval? That's what we were promised by your thread title. ***
_______________________________________________
My response
This is at least the second time that I stress this point.
All GOF (goodness of fit ) test are built in these terms
__1__The null hypotheses H0 is: the sample could eventually be drawn from the Distribution N? (Here, the normal distribution).
__2__If so, I am free to get a *sample statistics*, W, such that I find out the *cumulative probability* F(W) for the critical values.
__3__Considering the Jarque-Bera test, W is the same whatever the NORMAL mean and variance are. The trick is
____a) using the CENTRL moments
____b) using as for the SKEWNESS, S, as for the KURTOSIS, K, values that are reduced (division by variance raised to 3/2, square of the variance, respectively).
Because W is always positive we DEFINE the acceptance interval as [0, U: F(U) = 1-alpha]. This acceptance interval is such that if the test provides a value W0 < = U we are sure (at the significance level alpha) that H0 COULD NOT BE REJECTED: there are not sufficient evidence to do so.
On contrary if W0 > U we cannot accept H0, there ARE SUFFICIENT EVIDENCE that the sample was not drawn from a normal distribution (at the significance level alpha). ________________________________
The Jack´s INSISTENCE in deny the legitimacy of a GOF test (like Jarque-Bera) only because (I quote):
*** But what is the parameter that the confidence interval pertains to?***
clearly shows that Tomsk, besides unlearned in Hypotheses test, is prone to careless statements, and immensely STUPID.
________________________________
________licas (Luis A. Afonso) |
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| Jack Tomsky |
Posted: Thu Mar 08, 2007 11:08 am |
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Quote: Jack Tomsky wrote
*** What you've described is a statistical test for
the composite hypothesis of normality. But what is
the parameter that the confidence interval pertains
to? In other words, given a sample of size N, what
is your unknown parameter and what is your confidence
interval? That's what we were promised by your
thread title. ***
_______________________________________________
My response
This is at least the second time that I stress this
point.
All GOF (goodness of fit ) test are built in these
terms
__1__The null hypotheses H0 is: the sample could
eventually be drawn from the Distribution N? (Here,
the normal distribution).
__2__If so, I am free to get a *sample statistics*,
W, such that I find out the *cumulative probability*
F(W) for the critical values.
__3__Considering the Jarque-Bera test, W is the same
whatever the NORMAL mean and variance are. The trick
is
____a) using the CENTRL moments
____b) using as for the SKEWNESS, S, as for the
KURTOSIS, K, values that are reduced (division by
variance raised to 3/2, square of the variance,
respectively).
Because W is always positive we DEFINE the acceptance
interval as [0, U: F(U) = 1-alpha]. This acceptance
interval is such that if the test provides a value W0
= U we are sure (at the significance level alpha)
that H0 COULD NOT BE REJECTED: there are not
sufficient evidence to do so.
On contrary if W0 > U we cannot accept H0, there ARE
SUFFICIENT EVIDENCE that the sample was not drawn
from a normal distribution (at the significance level
alpha). ________________________________
The Jack´s INSISTENCE in deny the legitimacy of a GOF
test (like Jarque-Bera) only because (I quote):
*** But what is the parameter that the confidence
interval pertains to?***
clearly shows that Tomsk, besides unlearned in
Hypotheses test, is prone to careless statements, and
immensely STUPID.
________________________________
________licas (Luis A. Afonso)
This is false advertising. You mention confidence intervals in your title, but then you give no confidence intervals. You won't even identify the parameter. For all we know, you'll probably title your next thread "Fermat's Last Theorem".
Jack |
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| Luis A. Afonso |
Posted: Thu Mar 08, 2007 12:34 pm |
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As I did mention all the problematics concerning the Jarque- Bera test for finite sample size is clearly depicted in the Steve Lawford´s paper. I simply followed his procedure (Monte Carlo simulations) in order to define the acceptance intervals for the two ordinary significance levels, 5% and 1%. IMO my values are in agreement with the quantiles of Fig. 2, qhat 0.95.in function of the sample sizes. (0.99 ones are absent). I invite the Readers to consult it
______Finite-sample quantiles of the Jarque-Bera test.
______Steve Lawford (first draft Feb. 2004).
AFTER reading it I am really pleased to have a learned discussion on this matter. NOT BEFORE.
___Mouth-dance, NO, thank you.
_________licas (Luis A. Afonso)
Jack Tomsky wrote
*** What you've described is a statistical test for the composite hypothesis of normality. But what is the parameter that the confidence interval pertains to? In other words, given a sample of size N, what is your unknown parameter and what is your confidence interval? That's what we were promised by your thread title. ***
_______________________________________________
My response
This is at least the second time that I stress this point.
All GOF (goodness of fit ) test are built in these terms
__1__The null hypotheses H0 is: the sample could eventually be drawn from the Distribution N? (Here, the normal distribution).
__2__If so, I am free to get a *sample statistics*, W, such that I find out the *cumulative probability* C(W) for the critical values.
__3__Considering the Jarque-Bera test, W is the same whatever the NORMAL mean and variance are. The trick is
____a) using the CENTRL moments
____b) using as for the SKEWNESS, S, as for the KURTOSIS, K, values that are reduced (division by variance raised to 3/2, square of the variance, respectively).
Because W is always positive we DEFINE the acceptance interval as [0, U: p(C(W) = 1-alpha]. This acceptance interval is such that if the test provides a value W0 < = U we are sure (at the significance level alpha) that H0 COULD NOT BE REJECTED: there are not sufficient evidence to do so.
On contrary if W0 > U we cannot accept H0, there ARE SUFFICIENT EVIDENCE that the sample was not drawn from a normal distribution (at the significance level alpha). ________________________________
The Jack´s INSISTENCE in deny the legitimacy of a GOF test (like Jarque-Bera) only because (I quote):
*** But what is the parameter that the confidence interval pertains to?***
clearly shows that Tomsk, besides unlearned in Hypotheses test, is prone to careless statements, and immensely STUPID.
________________________________
________licas (Luis A. Afonso) |
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| Jack Tomsky |
Posted: Thu Mar 08, 2007 1:59 pm |
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Quote: As I did mention all the problematics concerning the
Jarque- Bera test for finite sample size is clearly
depicted in the Steve Lawford´s paper. I simply
followed his procedure (Monte Carlo simulations) in
order to define the acceptance intervals for the two
ordinary significance levels, 5% and 1%. IMO my
values are in agreement with the quantiles of Fig. 2,
qhat 0.95.in function of the sample sizes. (0.99 ones
are absent). I invite the Readers to consult it
______Finite-sample quantiles of the Jarque-Bera
test.
______Steve Lawford (first draft Feb. 2004).
AFTER reading it I am really pleased to have a
learned discussion on this matter. NOT BEFORE.
___Mouth-dance, NO, thank you.
_________licas (Luis A. Afonso)
So this has nothing to do with confidence intervals even though confidence intervals are in the title?
Jack
Quote:
Jack Tomsky wrote
*** What you've described is a statistical test for
the composite hypothesis of normality. But what is
the parameter that the confidence interval pertains
to? In other words, given a sample of size N, what
is your unknown parameter and what is your confidence
interval? That's what we were promised by your
thread title. ***
_______________________________________________
My response
This is at least the second time that I stress this
point.
All GOF (goodness of fit ) test are built in these
terms
__1__The null hypotheses H0 is: the sample could
eventually be drawn from the Distribution N? (Here,
the normal distribution).
__2__If so, I am free to get a *sample statistics*,
W, such that I find out the *cumulative probability*
C(W) for the critical values.
__3__Considering the Jarque-Bera test, W is the same
whatever the NORMAL mean and variance are. The trick
is
____a) using the CENTRL moments
____b) using as for the SKEWNESS, S, as for the
KURTOSIS, K, values that are reduced (division by
variance raised to 3/2, square of the variance,
respectively).
Because W is always positive we DEFINE the acceptance
interval as [0, U: p(C(W) = 1-alpha]. This acceptance
interval is such that if the test provides a value W0
= U we are sure (at the significance level alpha)
that H0 COULD NOT BE REJECTED: there are not
sufficient evidence to do so.
On contrary if W0 > U we cannot accept H0, there ARE
SUFFICIENT EVIDENCE that the sample was not drawn
from a normal distribution (at the significance level
alpha). ________________________________
The Jack´s INSISTENCE in deny the legitimacy of a GOF
test (like Jarque-Bera) only because (I quote):
*** But what is the parameter that the confidence
interval pertains to?***
clearly shows that Tomsk, besides unlearned in
Hypotheses test, is prone to careless statements, and
immensely STUPID.
________________________________
________licas (Luis A. Afonso) |
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| Luis A. Afonso |
Posted: Thu Mar 08, 2007 4:05 pm |
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I suppose I got what Jack problem is.
My goal is to test he null Hypotheses
____H0 : Could be the sample from a Normal Distribution? , against
____Ha : The distribution is not Normal.
For this I found
a)************ an ACCEPTANCE interval for H0 ******
which is bounded by a no-null,
b) ************* CRITICAL VALUE****************
which is completed by a
c) ***** NO-ACCEPTANCE (rejection) INTERVAL*****
to which is attached to a
d) *** SIGNIFICANCE LEVEL (alpha) PROBABILITY ***
What was my *error* ?
_________I CALLED a) confidence interval !!!!!!!!!!!!!
All the usefulness of typically empty and Byzantine ACADEMIC minds is to shout: HORROR ! , only for parameters is allowed to speak about confidence intervals!!!!!!!!!!
REALLY…
______________licas (Luis A. Afonso) |
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| Jack Tomsky |
Posted: Thu Mar 08, 2007 6:44 pm |
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Guest
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Quote: I suppose I got what Jack problem is.
My goal is to test he null Hypotheses
____H0 : Could be the sample from a Normal
Distribution? , against
____Ha : The distribution is not Normal.
For this I found
a)************ an ACCEPTANCE interval for H0 ******
which is bounded by a no-null,
b) ************* CRITICAL VALUE****************
which is completed by a
c) ***** NO-ACCEPTANCE (rejection) INTERVAL*****
to which is attached to a
d) *** SIGNIFICANCE LEVEL (alpha) PROBABILITY ***
What was my *error* ?
_________I CALLED a) confidence interval
!!!!!!!!!!!!!
All the usefulness of typically empty and Byzantine
ACADEMIC minds is to shout: HORROR ! , only for
parameters is allowed to speak about confidence
intervals!!!!!!!!!!
REALLY…
______________licas (Luis A. Afonso)
Congratulations, Luis, you finally got it. Now I suppose you won't treat acceptance intervals and confidence intervals as synonyms any longer.
Jack |
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| Luis A. Afonso |
Posted: Thu Mar 08, 2007 10:14 pm |
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Jack Tomsky wrote:
*** Congratulations, Luis, you finally got it. Now I suppose you won't treat acceptance intervals and confidence intervals as synonyms any longer. Jack ***
… which s equivalent of do not discern a difference between IDENTICAL TWINS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
__________IMBECILE.
_________licas (Luis A. Afonso) |
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| Jack Tomsky |
Posted: Fri Mar 09, 2007 4:21 am |
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Quote: Jack Tomsky wrote:
*** Congratulations, Luis, you finally got it. Now I
suppose you won't treat acceptance intervals and
confidence intervals as synonyms any longer. Jack
***
… which s equivalent of do not discern a difference
between IDENTICAL
TWINS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
__________IMBECILE.
_________licas (Luis A. Afonso)
Then let me rescind my congratulations if you still think that confidence intervals and acceptance intervals are identical twins.
Jack |
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