In Excel for the web, you can view the results of a regression analysis (in statistics, a way to predict and forecast trends), but you can't create one because the Regression tool isn't available.
You also won't be able to use a statistical worksheet function such as LINEST to do a meaningful analysis because it requires you enter it as an array formula, which isn't supported in Excel for the web.
If you have the Excel desktop application, you can use the Open in Excel button to open your workbook and use either the Analysis ToolPak's Regression tool or statistical functions to perform a regression analysis there.
Click Open in Excel and perform a regression analysis.
For news about the latest Excel for the web updates, visit the Microsoft Excel blog.