Google-analytics – Browser trending on Google Analytics (data normalization)

Unless you use custom variables, this is not possible, since Advanced Segments are visit based and not visitor based. Custom variables can however be set to be visitor specific.

E.g. you set custom var 1 to visitor level on the specified page according to Google's instructions (please use async code), examples here: http://code.google.com/apis/analytics/docs/tracking/gaTrackingCustomVariables.html

Actual code sample (added to the page code, before "_trackPageview"):

...

 _gaq.push(['_setCustomVar',
      1,                   // This custom var is set to slot #1.  Required parameter.
      'Returning purchasing visitor',     // The name acts as a kind of category for the user activity. Required parameter.
      'Yes',               // This value of the custom variable.  Required parameter.
      1                    // Sets the scope to visitor-level.  Optional parameter.
   ]);

...

Google defines unique visitors as "number of unduplicated (counted only once) visitors to your website over the course of a specified time period" http://support.google.com/googleanalytics/bin/answer.py?hl=en&answer=33087 so what is happening here is when you are looking at each day those numbers are correct for that day. When you expand the date range the numbers are different because you have 82 visitors (2334-2252=82) that came to the site on both days so they are counted as unique when you are looking at a single day but not when you are looking at two days.