Y = f(X)
Y = f(X) is a common mathematical expression which defines the relationship between the dependent variable 'Y' and the independent variable(s) 'X'. It is read as "Y as a function of X". f denotes the function and it explains the impact of X on Y. In lean six sigma terms, Y is the output metric while X(s) is/are the input metric(s).
An application-oriented question on the topic along with responses can be seen below. The best answer was provided by Prashanth Datta on 29th January 2019.
Applause for all the respondents- Prashanth Datta, Vastupal Vashisth, Mathi