Correction for attenuation: WAIS-IV and test X

UnnieE

New Member
Hi,

I have been asked to do a correction for attenuation of the context between a specific test (Lets call it test X) and a specific part-test of WAIS-IV (word understanding, lets call it test Y).

The reliability for WAIS-IV word understanding (test Y) is r = 0,85 and we assume that the observed correlation between scores on these tests is r = 0,73.

Can anybody help me solve this problem? google gave me very little information on this topic

Thanks beforehand

hlsmith

Less is more. Stay pure. Stay poor.
So you are trying to see how correlated two tests are? Is there a gold standard as well? I did not really following what your question was!

UnnieE

New Member
So you are trying to see how correlated two tests are? Is there a gold standard as well? I did not really following what your question was!
Hi! And yes i think that is what they want me to do. However i understand that it might be hard to understand my question because i tried to translate it. English is not my first language so i'm sorry for the translation mistakes. And no sorry we have not been given a golden standard or any examples.

spunky

Can't make spagetti
What is the reliability of test X? You need the reliabilities of both the WAIS-IV and test X to correct for attenuation.

hlsmith

Less is more. Stay pure. Stay poor.
And I am assuming reliability is established via a gold standard. Unless you are assuming WAIS is the gold-standard so you are trying to figure out where/how X is deviating!

spunky

Can't make spagetti
And I am assuming reliability is established via a gold standard. Unless you are assuming WAIS is the gold-standard so you are trying to figure out where/how X is deviating!
It seems to me (OP will let us know) that this more of a classroom-type exercise t where they want students to recognize how to use the correction-for-attenuation formula from Classical Test Theory

$$r_{x'y'} = \frac{r_{xy}}{\sqrt{r_{xx}r_{yy}}}$$

UnnieE

New Member
It seems to me (OP will let us know) that this more of a classroom-type exercise t where they want students to recognize how to use the correction-for-attenuation formula from Classical Test Theory

$$r_{x'y'} = \frac{r_{xy}}{\sqrt{r_{xx}r_{yy}}}$$
Hi! And thank you all for such quick answers. I will try my best to answer all your questions.

- The reliability of test X is unknown, this is a exam practice question and we are only provided with the details i listed in the start unfortunately

- And yes i think "spunky" is right that this is more based on learning the correction for attenuation formula, but i find it hard to use here since we have only been provided with the reliability for WAIS-IV word understanding (test Y) r = 0,85
and then the rest of the question goes on to say "And we assume that the observed correlation between scores on these tests is r = 0,73."

UnnieE

New Member
Important update! mystery solved

I contacted the teacher, and she sent me a sav file with the data sett of test X, so i think she wants me to calculate the reliability from that datasett by myself which is great because then it all makes sense. So i will calculate the r for test X, and i already have the r for test Y, and then i will just use the formula and everything should be just fine

Thank you everybody that commented and tried to help me! it is much appreciated.