ABSTRACT
In many cases of actual data analysis in various fields of applications, the data subject to the analysis are not acquired as initially planned. Data that have not been obtained in complete form as intended are called incomplete data. The incompleteness of data may take various forms. For example, part of the information may be observed, as in cases where the actual observation being sought may not be completely observed but is known to be greater than a certain value. On the contrary, no information may be obtained at all. A typical example of the former is censoring in survival time data, whereas the latter is treated as missing data.
