I have a question that has been bugging me lately. How is it that you determine the total error of a measurement? For example, if we are trying to measure the flow rate of water coming out of a hose. We let the water flowing through the hose fill a graduated cylinder and measure the time it takes to do it. So we would have: Flow rate = Volume / Time However lets say that we need to know the error of this measurement. Would we say that the total error is: Error = Ev*dQ/dv + Et*dQ/dt (d's are partial derivatives) Where, Q = function for flow rate Ev = max error from volume measurement Et = max error of time measurement Error = total error So the formula would ultimately be: Error = Et*-V/t^2 + Ev*1/t Would this be correct? Haven't done this in a while and its just not making sense to me?