This page contains key points with respect to Report Structure in Google Analytics
Setting the Active Date Range
To change your date range, click the arrow next to the active date range displayed at the upper right of all reports.
You can then use the Calendar or the Timeline to select a new date range.
The Calendar tab allows you to select date ranges by clicking on the day and month within the calendar or you can type dates in the Date Range boxes. The Timeline tab has a date slider that you can resize and move to cover any range of dates. You can see your the traffic of your site trends in the Timeline.
Setting a Comparison Date Range
You can select a date range to compare to the current selected date range.
When using the Timeline to set a comparison date range, you will see two date sliders instead of just one.
You can use a comparison date range to see how your site is performing month over month, year over year or even from one day to another.
The date range and comparison date ranges you select will apply to all your reports and graphs.
Graphing by day, Week, Month
Most reports include an over-time graph at the top. You can make this graph display data by a) day, b) week, or c) month.
You can also compare two metrics on the same graph to see how they are correlated. Click the arrow in the top left of the graph.
Then, click the Compare Two Metrics link and select which two metrics you want to compare.
In this example, we are graphing 1) visitors versus 2) average time on site.
Graph Roll Overs
You can roll your mouse over the graph and see actual numbers.