Significance level for correlations coefficients

Frequently asked questions about PLS path modeling.
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Ann Sardesai
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Significance level for correlations coefficients

Post by Ann Sardesai » Fri Dec 17, 2010 12:23 am

Hi,

Can anyone help with how i could determine the significance level or the pvalue for the correlations coeffcients in PLS?
Ann Sardesai

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Diogenes
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Post by Diogenes » Sat Jan 08, 2011 1:25 pm

Hi,
To the path coefficients, just run the Bootstrap algorithm to have the t-values (t > 1,96 are significant at 5%).

The actual version (2.0.M3) does not compute t-values to the correlations between LV.
You must copy/paste the LV standardized scores to another software to have these correlations and their probability of significances computed (SPSS in a parametric approach and Resampling for a bootstrap approach - http://www.uvm.edu/~dhowell/StatPages/R ... pling.html).

Best regards,

Bido

Bjerg54
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Post by Bjerg54 » Thu Mar 03, 2011 9:19 am

Hi Professor,

I have a question regarding the t-testing between the LV. If SmartPLS dosnt do this, then what are the results shown in "Path Coefficients (Mean, STDEV, T-Values)" when doing a bootstrap?
You get these results "T Statistics (|O/STERR|)" which I thought were the t-test results of the correlation between the LV's.

Another question regarding the test of a model. When evaluating the model, first I look at the outer model, then the inner model. Is there a meassure of significanse of the total model (outer+inner), not thinking about the r^2.

Kind regards,

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Diogenes
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Post by Diogenes » Thu Mar 03, 2011 4:54 pm

Hi,

Path coefficients are different from correlations.
These results (Mean...) are from path coefficients.

A general measure is the GoF, see:

viewtopic.php?t=1407&highlight=gof

Best regards,

Bido

Bjerg54
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Post by Bjerg54 » Fri Mar 04, 2011 9:53 am

Hi Diogenes,
Thank you for the reply.

Yes the path coefficient are as I understand the standardized versions of the linear regression weight results.

When describing the relationship between the LV, and calculating the impact on one LV when increasing another, which measurement would be recommended to use, the correlation or the path coefficient?

BR,
Wilke

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Post by mronkko » Tue Mar 08, 2011 6:06 am

Actually, you cannot estimate the significance of correlations with SPSS no more than you can estimate the significance of the path coefficients by comparing these to the appropriate t-distribution. The correlation between PLS scores does not follow any known sampling distribution, so you would need to bootstrap the confidence interval.

I do not think that SmartPLS can be used to estimate the significance of the correlations, since you would need to export the construct scores for each bootstrap sample.

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