WordPress "Site Stat" Issues

I am having issues with the statistic tracking on a clients WordPress site. Hopefully someone can help…

We built one site and copied that site and placed it on another domain. Both the sites work fine but the statistics are pulling information from both domains. So both sites read the exact same statistics. Is there something that I have to change in the wp-config file? Or maybe something with a database so they track the correct information?

Any help would be great.