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StatisticalTest

Computes p-values using statistical tests, optionally with correction for multiple hypotheses. Tests supported are: t-test, Wilcoxon rank sum and signed rank tests, Chi-squared, Fisher's exact test, F-test for variance, Shapiro-Wilk normality test, Kolmogorov-Smirnov and correlation tests (Pearson and Spearman). Tests can be paired/non-paired and two-sided/one-sided; not all combinations are relevant for some tests. If the data contain missing values, only non-missing values are used.

Several tests are computed in parallel. Tests can be computed for each row (when byRow=true) or for various column combinations (when byRow=false). If multiple hypothesis correction is enabled (using the correction parameter), corrected p-values are computed. Both are written to the pvalues output. Identifiers whose p-value is less than given threshold are written to the idlist output. If multiple hypothesis correction is enabled, threshold comparison is done using corrected p-values; otherwise, raw p-values are used.

Each tests needs one or two numeric vectors that are obtained from the input. The first vector is called target and the second reference. Some tests use only target (e.g. Shapiro). Some can use reference if present (e.g, t-test and Wilcoxon rank sum); otherwise, expected mean is supplied as parameter. If reference is not used, referenceColumns should be empty.

When byRow=true, targetColumns and referenceColumns give two lists of columns that are used for testing on each row; they can have different lengths, except when paired=true or with correlation tests. Column lists can also be obtained from the groups input if present. Identifiers for idlist are taken from the first column of the input matrix. The matrix2 input must not be present.

When byRow=false, targetColumns and referenceColumns must have equal length, denoted N. If reference is not used, referenceColumns is empty and targetColumn has N entries. Now, N tests are performed so that target values are taken from i'th column of targetColumns and reference values from the i'th column of referenceColumns on each iteration i. Identifiers for idlist have the format T_R, where T is a target column and R is a reference column. If two matrices are supplied, target values are taken from the first and reference values from the second. If the matrices have the same number of columns, targetColumns and referenceColumns can be set to * to test i'th column of matrix against i'th column of matrix2.

Correlation tests compute r and compare it to r=0; they return p-values and not correlation coefficients. Chi-squared and Fisher's exact test use contingency matrices for testing. These matrices are created from linear input vectors in column-major order so that [1 2 3 4] is considered as column vectors [1 2] and [3 4]. The number of rows in contingency matrices is set with contingencyRows.

Inputs

Outputs

Parameters

Test cases