The “Generic Stats” plugin is a place for you to put all statistics tracking code that the various stats packages provide in one place.
The benefit is that when swapping templates or adding (and removing) stats code, you don’t need to edit your theme.
You also have the option to specify which code will be put above the <body> tag, and which code will be placed BELOW the </body> tag.
You can also prevent the stats code from being shown to admin users, to prevent the tracking of admin users.
For more info on this plugin, you can go to the following pages: