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Thread Subject:
How to compare vectors of unequal length?

Subject: How to compare vectors of unequal length?

From: Jerry

Date: 26 Jul, 2012 17:00:17

Message: 1 of 5

Hello,

I am asking a basic statistical question; actually there are three vectors, including A, B and C, in that size (A ) is (90, 1), size (B ) is (900, 1), and size is (C ), (1800, 1). I need to statistically compare these three vectors. Please let me know whether there is a function to compare these vectors or whether there is a solution to adjust the size of these vectors before comparison.

Thanks,

Jerry

Subject: How to compare vectors of unequal length?

From: dpb

Date: 26 Jul, 2012 17:32:45

Message: 2 of 5

On 7/26/2012 12:00 PM, Jerry wrote:
> Hello,
>
> I am asking a basic statistical question; actually there are three
> vectors, including A, B and C, in that size (A ) is (90, 1), size (B )
> is (900, 1), and size is (C ), (1800, 1). I need to statistically
> compare these three vectors. Please let me know whether there is a
> function to compare these vectors or whether there is a solution to
> adjust the size of these vectors before comparison.
...

What, specifically would you want as a measure of comparison?

Or in statistical terms, develop the null hypothesis and that will lead
to a test statistic.

Sure, there are lots of ways to adjust the size of the vectors before
comparison -- some of them may be of marginal value but w/ no more
information than is provided they're just as valid as any other--

B(length(A)+1:end)=[];
C(length(A)+1:end)=[];

Now their lengths are adjusted.

--

Subject: How to compare vectors of unequal length?

From: Jerry

Date: 26 Jul, 2012 18:54:26

Message: 3 of 5

But, I don't want to loose the information at each vector. In other words, is there a function such as a modified ANOVA to deal with such type data, in that the length of each vector within a matrix is not the same?

Thanks,

Jerry
  
dpb <none@non.net> wrote in message <jurv00$sps$1@speranza.aioe.org>...
> On 7/26/2012 12:00 PM, Jerry wrote:
> > Hello,
> >
> > I am asking a basic statistical question; actually there are three
> > vectors, including A, B and C, in that size (A ) is (90, 1), size (B )
> > is (900, 1), and size is (C ), (1800, 1). I need to statistically
> > compare these three vectors. Please let me know whether there is a
> > function to compare these vectors or whether there is a solution to
> > adjust the size of these vectors before comparison.
> ...
>
> What, specifically would you want as a measure of comparison?
>
> Or in statistical terms, develop the null hypothesis and that will lead
> to a test statistic.
>
> Sure, there are lots of ways to adjust the size of the vectors before
> comparison -- some of them may be of marginal value but w/ no more
> information than is provided they're just as valid as any other--
>
> B(length(A)+1:end)=[];
> C(length(A)+1:end)=[];
>
> Now their lengths are adjusted.
>
> --
>

Subject: How to compare vectors of unequal length?

From: John D'Errico

Date: 26 Jul, 2012 19:18:11

Message: 4 of 5

"Jerry " <jerrycholo@gmail.com> wrote in message <jus3p2$mdq$1@newscl01ah.mathworks.com>...
> But, I don't want to loose the information at each vector. In other words, is there a function such as a modified ANOVA to deal with such type data, in that the length of each vector within a matrix is not the same?
>

You need to define what it means to compare things
that are not directly comparable. And, sadly, you will
find it difficult to do so statistically. Regardless, we
still have no idea of your intent, or of the nature of
your data. Given the two vectors

[1 4], [2 4 3]

How might they be compared? Unless we know what
those numbers mean and what we would compare, they
are pure numbers. Any comparison would yield pure
gibberish, as it rightly should.

John

Subject: How to compare vectors of unequal length?

From: Aftab MooShoo Bong Singh

Date: 27 Jul, 2012 04:44:02

Message: 5 of 5

On Thu, 26 Jul 2012 19:18:11 +0000, John D'Errico wrote:

> "Jerry " <jerrycholo@gmail.com> wrote in message
> <jus3p2$mdq$1@newscl01ah.mathworks.com>...
>> But, I don't want to loose the information at each vector. In other
>> words, is there a function such as a modified ANOVA to deal with such
>> type data, in that the length of each vector within a matrix is not the
>> same?
>>
>>
> You need to define what it means to compare things that are not directly
> comparable. And, sadly, you will find it difficult to do so
> statistically. Regardless, we still have no idea of your intent, or of
> the nature of your data. Given the two vectors
>
> [1 4], [2 4 3]
>
> How might they be compared? Unless we know what those numbers mean and
> what we would compare, they are pure numbers. Any comparison would yield
> pure gibberish, as it rightly should.
>
> John

wellll... they do look nice!
of course, there isn't any accounting for taste.

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