What is DEVSQ function in Excel? DEVSQ function is one of Statistical functions in Microsoft Excel that returns the sum of squares of deviations of data points from their sample mean. Syntax of DEVSQ function DEVSQ(number1, [number2], …) The DEVSQ function syntax has the following arguments: Number1, number2, …    Number1 is required, subsequent numbers are optional. 1 […]