1. A method of evaluating precision of output data based on error propagation, comprising: performing, by a processor, numerical differentiation using input data in data processing, to obtain a Jacobian matrix J of the data processing; estimating, by the processor, variance-covariance of errors of the input data, to obtain an error matrix D of the input data; and calculating, by the processor, an error matrix R from the Jacobian matrix J and the error matrix D of the input data, the error matrix R representing variance-covariance of errors of output data.