1. A system for monitoring and diagnosing on-line multivariate process variable data in a process plant, wherein the multivariate process data comprises a plurality of process variables each having a plurality of observations, the system comprising: a data collection tool adapted to collect on-line process data from a process control system within the process plant when the process is on-line, wherein the collected on-line process data comprises a plurality of observations of a plurality of process variables and wherein the plurality of observations of the set of collected process data comprises a first data space having a plurality of dimensions; a first analysis tool comprising a multivariate statistical analysis engine adapted to represent the operation of the process based on a set of collected on-line process data comprising a measure of the operation of the process when the process is on-line within a second data space having fewer dimensions than the first data space; a second analysis tool comprising a univariate analysis engine adapted to represent the operation of the process as a multivariate projection of the on-line process data by a univariate variable for each of the process variables, wherein the univariate variable unifies the process variables; and a display tool adapted to generate a visualization comprising a first plot of a result generated by the multivariate statistical representation of the operation of the process and a second plot of a result generated by the univariate representation of the operation of the process.