Fw: Re: too little data

[John F Hall]

On reflection, I think that was 3 x 3, not 2 x 2.

 

----- Original Message -----

From: [hidden email]

To: [hidden email]

Sent: Sunday, December 06, 2009 1:37 PM

Subject: Re: Re: too little data

I always understood that the maximum r on a 2 x 2 table was .707, but that was almost 40 years ago when SPSS first appeared in UK.

----- Original Message -----

From: [hidden email]

To: [hidden email]

Sent: Tuesday, December 01, 2009 10:09 PM

Subject: Re: too little data

Since variables are columns, if I create a data file within SPSS with:

3 3
5 5
2 2

and run a Pearson correlation, I get the expected 1.0, even with only 3
values per variable.  I'm kind of surprised with only 3 rows (too little
data), but indeed I got 1.0.

Cheers,
Necia A. Black, Ph.D.           e-mail:  [hidden email]
246 Computing Center            Web URL:http://www.acsu.buffalo.edu/~black
SUNY-Buffalo
Buffalo, New York 14260

On Tue, 1 Dec 2009, Sonia Brandon wrote:

> Hi Anata -
>
> Ruben is thinking exactly what I was.  Go into your table and expand the decimal field to see if you've got something like 2.79 instead of 3, etc.
>
> Sonia
>
> Sonia Brandon, Ph.D.
> Director, Institutional Research
> Mesa State College
> 1100 North Avenue
> Grand Junction, CO  81501
> phone: [phone]
> fax:  [phone]
> email: [hidden email]
>
>
>>>> Ruben van den Berg <[hidden email]> 12/1/2009 1:45 PM >>>
>
> Dear Anata,
>
>
>
> I've no idea! The only thing I can think of, is that the data only look like 3, 5, 2 in SPSS but that there's actually nonvisible decimals. What you see, is not what you get. If you run the syntax below, the data will look like 3, 5, 2 but the correlation will be only .76. Will the real v1 and v2 please stand up now? The last line of syntax will reveal their true nature (in this case at least).
>
>
>
> P.s. you may have to replace the comma decimal separators by periods.
>
>
>
> Kind regards,
>
>
>
> Ruben van den Berg
>
>
>
> data list free/v1 v2(2f1.0).
>
> begin data
>
> 2,5 3,49 5,49 4,5 2,49 1,5
>
> end data.
>
> cor v1 v2.
>
>
>
> for v1 v2(f3.2).
>
>
>
>
>
>
>
>
>
>
>
> Date: Tue, 1 Dec 2009 12:00:16 -0800
> From: [hidden email]
> Subject: too little data
> To: [hidden email]
>
>
>
>
>
> Hi!
>
> I am not a statistician so you may find my question silly, but I wonder why do I have:
> Var1: 3 5 2
> Var2: 3 5 2,
> and, with SPSS, I get a correlation of +0.8 instead of +1?
>
>
>
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