{{alias}}( W[, options] ) Returns an accumulator function which incrementally performs a moving Grubbs' test for detecting outliers. Grubbs' test assumes that data is normally distributed. Accordingly, one should first verify that the data can be reasonably approximated by a normal distribution before applying the Grubbs' test. The `W` parameter defines the number of values over which to perform Grubbs' test. The minimum window size is 3. If provided a value, the accumulator function returns updated test results. If not provided a value, the accumulator function returns the current test results. Until provided `W` values, the accumulator function returns `null`. The accumulator function returns an object having the following fields: - rejected: boolean indicating whether the null hypothesis should be rejected. - alpha: significance level. - criticalValue: critical value. - statistic: test statistic. - df: degrees of freedom. - mean: sample mean. - sd: corrected sample standard deviation. - min: minimum value. - max: maximum value. - alt: alternative hypothesis. - method: method name. - print: method for pretty-printing test output. Parameters ---------- W: integer Window size. options: Object (optional) Function options. options.alpha: number (optional) Significance level. Default: 0.05. options.alternative: string (optional) Alternative hypothesis. The option may be one of the following values: - 'two-sided': test whether the minimum or maximum value is an outlier. - 'min': test whether the minimum value is an outlier. - 'max': test whether the maximum value is an outlier. Default: 'two-sided'. Returns ------- acc: Function Accumulator function. Examples -------- > var acc = {{alias}}( 20 ); > var res = acc() null > for ( var i = 0; i < 200; i++ ) { ... res = acc( {{alias:@stdlib/random/base/normal}}( 10.0, 5.0 ) ); ... }; > res.print() References ---------- - Grubbs, Frank E. 1950. "Sample Criteria for Testing Outlying Observations." _The Annals of Mathematical Statistics_ 21 (1). The Institute of Mathematical Statistics: 27–58. doi:10.1214/aoms/1177729885. - Grubbs, Frank E. 1969. "Procedures for Detecting Outlying Observations in Samples." _Technometrics_ 11 (1). Taylor & Francis: 1–21. doi:10.1080/ 00401706.1969.10490657. See Also --------