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  2. pandas (software) - Wikipedia

    en.wikipedia.org/wiki/Pandas_(software)

    For example, df.groupby(lambda i: i % 2) groups data by whether the index is even. [4]: 253–259 Pandas includes support for time series, such as the ability to interpolate values [4]: 316–317 and filter using a range of timestamps (e.g. data['1/1/2023':'2/2/2023'] will return all dates between January 1st and February 2nd).

  3. Grouped data - Wikipedia

    en.wikipedia.org/wiki/Grouped_data

    Another method of grouping the data is to use some qualitative characteristics instead of numerical intervals. For example, suppose in the above example, there are three types of students: 1) Below normal, if the response time is 5 to 14 seconds, 2) normal if it is between 15 and 24 seconds, and 3) above normal if it is 25 seconds or more, then the grouped data looks like:

  4. Data transformation (statistics) - Wikipedia

    en.wikipedia.org/wiki/Data_transformation...

    Examples of variance-stabilizing transformations are the Fisher transformation for the sample correlation coefficient, the square root transformation or Anscombe transform for Poisson data (count data), the Box–Cox transformation for regression analysis, and the arcsine square root transformation or angular transformation for proportions ...

  5. Aggregate function - Wikipedia

    en.wikipedia.org/wiki/Aggregate_function

    Range; Sum; Others include: Nanmean (mean ignoring NaN values, also known as "nil" or "null") Stddev; Formally, an aggregate function takes as input a set, a multiset (bag), or a list from some input domain I and outputs an element of an output domain O. [1] The input and output domains may be the same, such as for SUM, or may be different ...

  6. Count data - Wikipedia

    en.wikipedia.org/wiki/Count_data

    Graphical examination of count data may be aided by the use of data transformations chosen to have the property of stabilising the sample variance. In particular, the square root transformation might be used when data can be approximated by a Poisson distribution (although other transformation have modestly improved properties), while an inverse sine transformation is available when a binomial ...

  7. Power transform - Wikipedia

    en.wikipedia.org/wiki/Power_transform

    In statistics, a power transform is a family of functions applied to create a monotonic transformation of data using power functions.It is a data transformation technique used to stabilize variance, make the data more normal distribution-like, improve the validity of measures of association (such as the Pearson correlation between variables), and for other data stabilization procedures.

  8. Count-distinct problem - Wikipedia

    en.wikipedia.org/wiki/Count-distinct_problem

    In computer science, the count-distinct problem [1] (also known in applied mathematics as the cardinality estimation problem) is the problem of finding the number of distinct elements in a data stream with repeated elements. This is a well-known problem with numerous applications.

  9. Anscombe transform - Wikipedia

    en.wikipedia.org/wiki/Anscombe_transform

    In statistics, the Anscombe transform, named after Francis Anscombe, is a variance-stabilizing transformation that transforms a random variable with a Poisson distribution into one with an approximately standard Gaussian distribution. The Anscombe transform is widely used in photon-limited imaging (astronomy, X-ray) where images naturally ...