Of course, you'll need to have a Google account and be logged in to use the service. Once you've done so, you can control all of the data that you would normally access from your web browser, now from the comfort of your smartphone.
So, you can view the number of daily visits along a week, the average amount of time they spend on your site, where they come from, how your Google Adsense (if you use it) is performing, and a lot of other interesting information.
Google Analytics is an extremely useful application for website owners, administrators, and basically anyone who usually accesses the online Analytics service. Thanks to this app, you can do it all without having to start up your computer.