# How do you average Ki values?

It's embarrassing for me to ask this but well such is life. NIMH Psychoactive Drug Screening Program (PDSP) Ki Database is mentioned as the source of the average binding affinity (Ki) values given in Goodman and Gilman but whenever I try to, in some way, confirm that these values are averages obtained from PDSP I get values that are way (up to 10,000 fold) off the values given in Goodman and Gilman. (ps. I am a mathematician too so I know how to take an average, $\bar{x} = \frac{\sum_i^n x_i}{n}$ so you don't need to hold my hand through the calculation with something as simple as the conventional definition of averages) Therefore I have reached the conclusion that I must be doing the calculations wrong. Please show me how to do them correctly. Here's a screenshot of exactly what Goodman and Gilman says that's confusing me:

Oh and yes I am using just the cloned human transporter values not just all the stuff that comes up.

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check the units.. may be a μM to nM conversion problem.. verify – WYSIWYG Apr 30 '13 at 4:51
Nope, all the units are nM. – Brenton Horne Apr 30 '13 at 5:14
it would be better if you can save this page as a document or pdf and put it in dropbox. Or if there is an ebook then please provide the url if it is possible. – WYSIWYG Apr 30 '13 at 8:50
The latter would be a breach of copyright and the other I don't quite understand how that would be better. – Brenton Horne Apr 30 '13 at 8:55
Sharing the URL: if it is open such as in the books in the NCBI site. Better: so that i dont need to zoom in to see. – WYSIWYG Apr 30 '13 at 10:24