The Mahalanobis Taguchi (MT) and the recognition Taguchi (RT) methods are typical methods of the MT system and are, used for discrimination of multivariate data such as bankruptcy judgement of a company, medical checkup, and character recognition. They have a common problem regarding how missing data are handled. The use of these methods requires the assumption that normal samples are obtained from a homogenous space known as a unit space. Therefore, it is necessary to prepare sufficient samples for analysis.
We first apply multiple imputation to the MT method, the MI-MT method. However, the MT method has a restriction that analysis cannot be performed if the sample size is smaller than the number of variables. Even if the sample size is larger, it is reported that if the sample size is not sufficient, the results will be unstable. On the other hand, the RT method reduces to two variables, so it is not easily affected by the sample size. Therefore, we apply multiple imputation to the RT method, the MI-RT method. Monte Carlo simulation, is used to investigate the accuracy of MI-MT and MI-RT. We conclude that MI-MT and MI-RT are better than MT and RT using other imputation methods.
View full abstract