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  2. dplyr - Wikipedia

    en.wikipedia.org/wiki/Dplyr

    arrange(), which is used to sort rows in a dataframe based on attributes held by particular columns; mutate(), which is used to create new variables, by altering and/or combining values from existing columns; and; summarize(), also spelled summarise(), which is used to collapse values from a dataframe into a single summary.

  3. Design matrix - Wikipedia

    en.wikipedia.org/wiki/Design_matrix

    The design matrix has dimension n-by-p, where n is the number of samples observed, and p is the number of variables measured in all samples. [4] [5]In this representation different rows typically represent different repetitions of an experiment, while columns represent different types of data (say, the results from particular probes).

  4. Simple random sample - Wikipedia

    en.wikipedia.org/wiki/Simple_random_sample

    For example, if a teacher has a class arranged in 5 rows of 6 columns and she wants to take a random sample of 5 students she might pick one of the 6 columns at random. This would be an epsem sample but not all subsets of 5 pupils are equally likely here, as only the subsets that are arranged as a single column are eligible for selection.

  5. Random number table - Wikipedia

    en.wikipedia.org/wiki/Random_number_table

    In the 1950s, a hardware random number generator named ERNIE was used to draw British premium bond numbers. The first "testing" of random numbers for statistical randomness was developed by M.G. Kendall and B. Babington Smith in the late 1930s, and was based upon looking for certain types of probabilistic expectations in a given sequence. The ...

  6. Data set - Wikipedia

    en.wikipedia.org/wiki/Data_set

    Various plots of the multivariate data set Iris flower data set introduced by Ronald Fisher (1936). [1]A data set (or dataset) is a collection of data.In the case of tabular data, a data set corresponds to one or more database tables, where every column of a table represents a particular variable, and each row corresponds to a given record of the data set in question.

  7. Table (database) - Wikipedia

    en.wikipedia.org/wiki/Table_(database)

    In a database, a table is a collection of related data organized in table format; consisting of columns and rows.. In relational databases, and flat file databases, a table is a set of data elements (values) using a model of vertical columns (identifiable by name) and horizontal rows, the cell being the unit where a row and column intersect. [1]

  8. Random projection - Wikipedia

    en.wikipedia.org/wiki/Random_projection

    The random matrix R can be generated using a Gaussian distribution. The first row is a random unit vector uniformly chosen from . The second row is a random unit vector from the space orthogonal to the first row, the third row is a random unit vector from the space orthogonal to the first two rows, and so on.

  9. Random permutation statistics - Wikipedia

    en.wikipedia.org/wiki/Random_permutation_statistics

    The mathematical statement of this problem is as follows: pick a random permutation on n elements and k values from the range 1 to n, also at random, call these marks. What is the probability that there is at least one mark on every cycle of the permutation? The claim is this probability is k/n.