1. A computer-readable storage medium storing a program for verifying an accuracy for model parameters computation, wherein the program causes a computer to perform a process comprising: reading a model represented by difference equations from a storage apparatus; computing difference equations that use numeric values of a time-series by replacing variables of the model with numeric values of a time-series that are stored in the storage apparatus; preparing first constraint equations by implementing, to the difference equations using the numeric values of a time-series, error variables corresponding to the difference equations; preparing second constraint equations including inequality equations in which a maximum value of an absolute value of each of the implemented error variables is set as an emax value; determining the emax value by applying a quantifier elimination method to constraint equations including the first and the second constraint equations; obtaining third constraint equations by substituting the emax value into the second constraint equation; determining ranges of parameters of the model by applying a quantifier elimination method to constraint equations including the first and the third constraint equations; verifying numbers of significant figures that show a degree of computation accuracy of model parameters by the determined ranges of parameters of the model; and upon a degree of computation accuracy of the model parameters being verified as less than a predetermined degree by the verification of numbers of significant figures, repeating operations in and after the reading the model after executing a processing of enhancing the degree of computation accuracy, wherein the processing of enhancing the degree of computation accuracy is an adjustment of numbers of significant figures of numeric values of input data including variables.