1. A computer-implemented method wherein the computer performs the following functions comprising: providing a multi-step mathematical process for simultaneously determining operating conditions of a system or process that will result in optimum performance for both mean performance requirements and robustness requirements, wherein the multi-step process utilizes a first set of data that includes independent variables to generate a second set of data used to optimize performance for both mean performance requirements and robustness requirements; wherein the first set of data will be derived from a rigorous statistical experiment design and/or historical data; wherein the first set of data is utilized to derive mean performance prediction models; and wherein the multi-step process includes: creating a parameter-based propagation-of-error matrix template (PPOE template) based on the experiment variables and their associated control limits; using the PPOE template to generate a joint probability of occurrence matrix (P j matrix) by computing a P j value for each PPOE template combination of the experiment variables; using the PPOE template to generate a response prediction matrix (Y pred matrix) by computing a Y pred value for each PPOE template combination of the experiment variables; transforming acceptance limits (±AL) for the response to actual lower and upper acceptance limits (LAL and UAL) around the Y pred value calculated for the setpoint level settings of the variables in preparation of calculating a response robustness (C p ); for each element in the Y pred matrix, centering the response prediction model error distribution about the mean predicted value and calculating the proportional amount of the distribution that is outside the response acceptance limits resulting in a φ matrix; transforming the data distribution of the matrix values from a uniform distribution to a Gaussian distribution; calculating the failure rate at setpoint (FRSP), wherein the FRSP is the proportion of the predicted response distribution that is outside the acceptance limits; calculating the standard deviation of the predicted response distribution using the FRSP; calculating the confidence interval of the predicted response distribution (CI prd ); calculating the C p for a given row in the first data set using the CI prd obtained and the actual response acceptance limits, resulting in robustness data from which a robustness prediction model is derived; and displaying the derived robustness prediction model.