1. A data analysis system comprising: a first subprocess to estimate the performance of a data classification model using a data set being partitioned into N non-overlapping and balanced subsets and a first cross-validation procedure; a second subprocess to choose an optimal set of parameters for the data classification model using the N non-overlapping and balanced subsets and a second cross-validation procedure; and a third subprocess to simultaneously perform optimal model selection and estimate performance of the data classification model using the N non-overlapping and balanced subsets and a nested cross-validation procedure; and a fourth subprocess to apply obtained model to classify new data.