Regression analysis in Excel can be performed using two primary methods. The first method involves the "=LINEST()" function, which provides statistical information about a linear regression model. The second method utilizes the Excel Analysis ToolPak Add-In, accessible under the "Data Analysis" option in the "Tools" menu, which offers a built-in regression routine. If the Analysis ToolPak is not visible, it can be installed through the Add-Ins menu. These methods allow users to calculate the correlation coefficient and coefficient of determination effectively.