BiweightLocation
✖
BiweightLocation

gives the value of the biweight location estimator of the elements in list.
gives the value of the biweight location estimator with scaling parameter c.
Details and Options

- BiweightLocation is a robust location estimator.
- BiweightLocation is given by a weighted mean of the elements. Elements farther from the center have lower weights.
- The width scale of the weight function is controlled by a parameter c. Larger c indicates more data values are included in the computation of the statistic, and vice versa.
- For the list {x1,x2,…,xn}, the value of the biweight location estimator is given by
, where
and
is Median[{x1-x*,x2-x*,…,xn-x*}]. The value x* of the estimator is computed iteratively, with the initial value chosen automatically by default.
- BiweightLocation[list] is equivalent to BiweightLocation[list,6].
- BiweightLocation[{{x1,y1,…},{x2,y2,…},…}] gives {BiweightLocation[{x1,x2,…}],BiweightLocation[{y1,y2,…}],…}.
- BiweightLocation allows c to be any positive real number.
- The following options can be given:
-
AccuracyGoal Automatic the accuracy sought MaxIterations Automatic maximum number of iterations to use Method Automatic method to use PrecisionGoal Automatic the precision sought WorkingPrecision MachinePrecision the precision used in internal computations - The setting Method{"InitialPoint"x0} allows for a custom initial value
.
Examples
open allclose allBasic Examples (4)Summary of the most common use cases
BiweightLocation of a list:

https://wolfram.com/xid/0elwwaq720ijq1u-wd9

BiweightLocation of columns of a matrix:

https://wolfram.com/xid/0elwwaq720ijq1u-vu6sr

BiweightLocation of a list with scaling parameter 7:

https://wolfram.com/xid/0elwwaq720ijq1u-whtpl

BiweightLocation of a list of dates:

https://wolfram.com/xid/0elwwaq720ijq1u-816jz2


https://wolfram.com/xid/0elwwaq720ijq1u-ziof1v

Scope (8)Survey of the scope of standard use cases
Same inputs with different precisions:

https://wolfram.com/xid/0elwwaq720ijq1u-m1jrh


https://wolfram.com/xid/0elwwaq720ijq1u-cufswv

Biweight location with different scaling parameters:

https://wolfram.com/xid/0elwwaq720ijq1u-fgu628


https://wolfram.com/xid/0elwwaq720ijq1u-bdt2rg

Biweight location for a matrix gives columnwise estimate:

https://wolfram.com/xid/0elwwaq720ijq1u-jywoa6

Biweight location of a large array:

https://wolfram.com/xid/0elwwaq720ijq1u-enve04


https://wolfram.com/xid/0elwwaq720ijq1u-if5yx4

Find a biweight location of a TimeSeries:

https://wolfram.com/xid/0elwwaq720ijq1u-tg8p6z

https://wolfram.com/xid/0elwwaq720ijq1u-ffhpdi

The biweight location depends only on the values:

https://wolfram.com/xid/0elwwaq720ijq1u-fy9fte

Biweight location works with data involving quantities:

https://wolfram.com/xid/0elwwaq720ijq1u-jopin9


https://wolfram.com/xid/0elwwaq720ijq1u-e8c21s

Compute biweight location of dates:

https://wolfram.com/xid/0elwwaq720ijq1u-b1smxx

https://wolfram.com/xid/0elwwaq720ijq1u-pa4nmn


https://wolfram.com/xid/0elwwaq720ijq1u-uok1il

Compute biweight location of times:

https://wolfram.com/xid/0elwwaq720ijq1u-et9bla


https://wolfram.com/xid/0elwwaq720ijq1u-ztsexm

List of times with different time zone specifications:

https://wolfram.com/xid/0elwwaq720ijq1u-mrqghz


https://wolfram.com/xid/0elwwaq720ijq1u-ow7hca

Options (2)Common values & functionality for each option
MaxIterations (1)
The value of BiweightLocation is computed iteratively. Limit the number of iterations attempted in the computation:

https://wolfram.com/xid/0elwwaq720ijq1u-t4f2u



https://wolfram.com/xid/0elwwaq720ijq1u-ccn2um

Method (1)
Adjust the starting value in the computation of BiweightLocation:

https://wolfram.com/xid/0elwwaq720ijq1u-bnyqh7

Limit the number of iterations with a better starting value:

https://wolfram.com/xid/0elwwaq720ijq1u-geb7yq


https://wolfram.com/xid/0elwwaq720ijq1u-hfvwgu


Applications (3)Sample problems that can be solved with this function
Obtain a robust estimate of location when outliers are present:

https://wolfram.com/xid/0elwwaq720ijq1u-cexxtn

Extreme values have a large influence on the Mean:

https://wolfram.com/xid/0elwwaq720ijq1u-blrzc0

Consider data from a Gaussian mixture distribution:

https://wolfram.com/xid/0elwwaq720ijq1u-pdvjh

https://wolfram.com/xid/0elwwaq720ijq1u-lh1q3

Estimate the center with Mean:

https://wolfram.com/xid/0elwwaq720ijq1u-e2rlxq

The sample mean estimator has a large spread for non-Gaussian data. The standard deviation of the estimator is:

https://wolfram.com/xid/0elwwaq720ijq1u-ew32qb

Estimate the center with BiweightLocation:

https://wolfram.com/xid/0elwwaq720ijq1u-bodwok

Use bootstrapping to assess the spread of the biweight location estimator:

https://wolfram.com/xid/0elwwaq720ijq1u-djtyv9

Simulate a trajectory with heavy-tailed measurement noise:

https://wolfram.com/xid/0elwwaq720ijq1u-f63fz9
The underlying signal and simulated path with noise:

https://wolfram.com/xid/0elwwaq720ijq1u-fh1mi1

Smooth the trajectory using a moving BiweightLocation:

https://wolfram.com/xid/0elwwaq720ijq1u-l6h0g9

https://wolfram.com/xid/0elwwaq720ijq1u-brc3ht
Increasing the block size gives a smoother trajectory:

https://wolfram.com/xid/0elwwaq720ijq1u-bb2lqb

Properties & Relations (3)Properties of the function, and connections to other functions
Compute the biweight location of a sample:

https://wolfram.com/xid/0elwwaq720ijq1u-dcvsx3

https://wolfram.com/xid/0elwwaq720ijq1u-ctetjg

Values outside of the interval have no effect on the statistic. Here
is the value of biweight location and
is the median absolute deviation with respect to
.
is a scaling parameter with default value equal to 6:

https://wolfram.com/xid/0elwwaq720ijq1u-fi8qr

The shape of the weight function w(x) being used in computing biweight location:

https://wolfram.com/xid/0elwwaq720ijq1u-d006dh

Multiply the smallest and the largest values in the sample by 2 and compute the biweight location again:

https://wolfram.com/xid/0elwwaq720ijq1u-jyiz5y

https://wolfram.com/xid/0elwwaq720ijq1u-eup6o0


https://wolfram.com/xid/0elwwaq720ijq1u-dgbfj

For normally distributed samples, BiweightLocation and Mean are nearly the same:

https://wolfram.com/xid/0elwwaq720ijq1u-by15b

https://wolfram.com/xid/0elwwaq720ijq1u-meq


https://wolfram.com/xid/0elwwaq720ijq1u-q6v

For non-normally distributed samples such as data from CauchyDistribution, BiweightLocation gives a better estimate of the center location than Mean:

https://wolfram.com/xid/0elwwaq720ijq1u-cojhy

https://wolfram.com/xid/0elwwaq720ijq1u-eirtoh


https://wolfram.com/xid/0elwwaq720ijq1u-zp5ly

BiweightLocation approaches Mean for large values of c:

https://wolfram.com/xid/0elwwaq720ijq1u-dy2d21

https://wolfram.com/xid/0elwwaq720ijq1u-szhr8g


https://wolfram.com/xid/0elwwaq720ijq1u-ed6bml

Neat Examples (2)Surprising or curious use cases
Variation of biweight location around the mean of univariate data depending on the scaling factor c:

https://wolfram.com/xid/0elwwaq720ijq1u-roz442

https://wolfram.com/xid/0elwwaq720ijq1u-oc0fak

https://wolfram.com/xid/0elwwaq720ijq1u-zyrwho

Variation of biweight location around the mean of bivariate data depending on the scaling factor c:

https://wolfram.com/xid/0elwwaq720ijq1u-xlb6lc

Wolfram Research (2017), BiweightLocation, Wolfram Language function, https://reference.wolfram.com/language/ref/BiweightLocation.html (updated 2024).
Text
Wolfram Research (2017), BiweightLocation, Wolfram Language function, https://reference.wolfram.com/language/ref/BiweightLocation.html (updated 2024).
Wolfram Research (2017), BiweightLocation, Wolfram Language function, https://reference.wolfram.com/language/ref/BiweightLocation.html (updated 2024).
CMS
Wolfram Language. 2017. "BiweightLocation." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2024. https://reference.wolfram.com/language/ref/BiweightLocation.html.
Wolfram Language. 2017. "BiweightLocation." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2024. https://reference.wolfram.com/language/ref/BiweightLocation.html.
APA
Wolfram Language. (2017). BiweightLocation. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/BiweightLocation.html
Wolfram Language. (2017). BiweightLocation. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/BiweightLocation.html
BibTeX
@misc{reference.wolfram_2025_biweightlocation, author="Wolfram Research", title="{BiweightLocation}", year="2024", howpublished="\url{https://reference.wolfram.com/language/ref/BiweightLocation.html}", note=[Accessed: 13-May-2025
]}
BibLaTeX
@online{reference.wolfram_2025_biweightlocation, organization={Wolfram Research}, title={BiweightLocation}, year={2024}, url={https://reference.wolfram.com/language/ref/BiweightLocation.html}, note=[Accessed: 13-May-2025
]}