When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Data cleansing - Wikipedia

    en.wikipedia.org/wiki/Data_cleansing

    Set-Membership constraints: The values for a column come from a set of discrete values or codes. For example, a person's sex may be Female, Male, or Non-Binary. Foreign-key constraints: This is the more general case of set membership. The set of values in a column is defined in a column of another table that contains unique values.

  3. Missing data - Wikipedia

    en.wikipedia.org/wiki/Missing_data

    The expectation-maximization algorithm is an approach in which values of the statistics which would be computed if a complete dataset were available are estimated (imputed), taking into account the pattern of missing data. In this approach, values for individual missing data-items are not usually imputed.

  4. Fisher's exact test - Wikipedia

    en.wikipedia.org/wiki/Fisher's_exact_test

    The smaller the value of p, the greater the evidence for rejecting the null hypothesis; so here the evidence is strong that men and women are not equally likely to be studiers. For a two-tailed test we must also consider tables that are equally extreme, but in the opposite direction. Unfortunately, classification of the tables according to ...

  5. Null object pattern - Wikipedia

    en.wikipedia.org/wiki/Null_object_pattern

    In object-oriented computer programming, a null object is an object with no referenced value or with defined neutral (null) behavior.The null object design pattern, which describes the uses of such objects and their behavior (or lack thereof), was first published as "Void Value" [1] and later in the Pattern Languages of Program Design book series as "Null Object".

  6. Nullable type - Wikipedia

    en.wikipedia.org/wiki/Nullable_type

    Nullable types are a feature of some programming languages which allow a value to be set to the special value NULL instead of the usual possible values of the data type.In statically typed languages, a nullable type is an option type, [citation needed] while in dynamically typed languages (where values have types, but variables do not), equivalent behavior is provided by having a single null ...

  7. Exploratory data analysis - Wikipedia

    en.wikipedia.org/wiki/Exploratory_data_analysis

    The distribution of values is skewed right and unimodal, as is common in distributions of small, non-negative quantities. Histogram of tip amounts where the bins cover $0.10 increments. An interesting phenomenon is visible: peaks occur at the whole-dollar and half-dollar amounts, which is caused by customers picking round numbers as tips.

  8. Random sample consensus - Wikipedia

    en.wikipedia.org/wiki/Random_sample_consensus

    Random sample consensus (RANSAC) is an iterative method to estimate parameters of a mathematical model from a set of observed data that contains outliers, when outliers are to be accorded no influence [clarify] on the values of the estimates. Therefore, it also can be interpreted as an outlier detection method. [1]

  9. Null (SQL) - Wikipedia

    en.wikipedia.org/wiki/Null_(SQL)

    In SQL, null or NULL is a special marker used to indicate that a data value does not exist in the database. Introduced by the creator of the relational database model, E. F. Codd , SQL null serves to fulfill the requirement that all true relational database management systems ( RDBMS ) support a representation of "missing information and ...