In a computer file for a survey, unanswered questions and those with answers like "Don't know" are declared to be missing values, and are usually excluded when calculating percentages etc. Sometimes, missing values can be guesstimated using imputation.
The value for an attribute is not known or does not exist. There are several possible reasons for a value to be missing, such as: it was not measured; there was an instrument malfunction; the attribute does not apply, or the attribute's value cannot be known. Some algorithms have problems dealing with missing values.
a value in the SAS System indicating that no data is stored for the column in the current row. By default, the SAS System prints a missing numeric value as a single period (.) and a missing character value as a blank space.
Data value that is missing because it was not measured (that is, has a null value), not answered, was unknown or was lost. Data mining methods vary in the way they treat missing values. Typically, they ignore the missing values, or omit any records containing missing values, or replace missing values with the mode or mean, or infer missing values from existing values.
A data value that is missing because it was not measured (that is, has a null value), not answered, was unknown, or was lost. Data mining systems vary in the way they treat missing values. There are several typical ways to treat them: ignore then, omit any records containing missing values, replace missing values with the mode or mean, or infer missing values from existing values. ODM ignores missing values during mining operations. mixture model A mixture model is a type of density model that includes several component functions (usually Gaussian) that are combined to provide a multimodal density.
A value code that indicates no data are present for a variable for a particular case. To be distinguished from non-response values (respondent refused to answer or was not asked the question) and from invalid responses (the response did not have a valid value code equivalent). Non-responses and invalid responses may or may not have value categories provided in the questionnaire and may be treated differently from true missing data during analysis.
A special value for a variable or array element indicating that no legal data has been specified for that quantity.
a value in SAS software that indicates that no data are stored in the variable for the current observation. By default, SAS software represents a missing numeric value with a single period, and a missing character value is represented by a blank space.
A value omitted from an equation that is needed to make the equation true. Example: ( 3 * 4 ) + X = 16.