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Correlations with ordinals

Hi,

 

From correlations results in design evaluation I don’t understand how you estimate the correlation of

• an ordinal and a continues factor and
•  the correlation between two ordinals.

 

If I understand correctly, the correlation between continues is the absolute value of Pearson correlation but what is it when ordinals are involved?

I can see that in ordinals the available correlations are (nr of levels) - 1 but I’m not sure how to calculate these correlations.

As example the ordinal variable X3 is represented by X3 1 and X3 2, but no X3 3.  
However when the X3 is evaluated against the other ordinal X4 the correlations are for the whole X3 vs specific X4 levels (i.e. X3*X4 1 and X3*X4 2 - so all X4 levels)

 

Thanks for your time.

EV

Sharing and Communicating ResultsRe: Correlations with ordinals

Hi, 

Thanks for your answer.
However, I'm not sure I understand how to do that. I understand that is not as simple as to get the desing matrix and check for the correlations. 

I need to have the model matrix which means that I have to set a model firstly. But then, what? 

How to find the model matrix on JMP? 
And how to expand the model matrix using my DoE?

And then on expanded matrix what I do to find the correaltion? 

 

Thanks for your time