If you have linear data and you want just the slope and intercept, use
functions SLOPE and INTERCEPT. For more statistics use LINEST
LINEST can also be used for non-linear fits; see
http://people.stfx.ca/bliengme/ExcelTips/Polynomial.htm
If you wish to use the static Data Analysis tool, you need to load the
Analysis ToolPak.
Click the Office button (bright star to the left), locate Excel Options at
bottom of dialog, in the left panel click AddIns, at the bottom of next
dialog use Manage Addins, click Go
Now make sure the Analysis ToolPak (first one, not the VBA one) is selected.
When you exit the options and look on the Data tab you will see Data
Analysis in the Analysis group
best wishes