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Statistics

GeometricMean

compute the geometric mean

Calling Sequence

GeometricMean(A, ds_options)

GeometricMean(M, ds_options)

GeometricMean(X, rv_options)

Parameters

X

-

algebraic; random variable or distribution

ds_options

-

(optional) equation(s) of the form option=value where option is one of ignore, or weights; specify options for computing the mean of a data set

rv_options

-

(optional) equation of the form numeric=value; specifies options for computing the mean of a random variable

Description

The GeometricMean function computes the geometric mean of the specified random variable or data set.

The first parameter can be a data set (e.g., a Vector ), a Matrix data set , a distribution (see Statistics[Distribution] ), a random variable, or an algebraic expression involving random variables (see Statistics[RandomVariable] ).

Computation

By default, all computations involving random variables are performed symbolically (see option numeric below).

All computations involving data are performed in floating-point; therefore, all data provided must have type/realcons and all returned solutions are floating-point, even if the problem is specified with exact values.

For more information about computation in the Statistics package, see the Statistics[Computation] help page.

Data Set Options

The ds_options argument can contain one or more of the options shown below. More information for some options is available in the Statistics[DescriptiveStatistics] help page.

ignore=truefalse -- This option controls how missing data is handled by the GeometricMean command. Missing items are represented by undefined or Float(undefined). So, if ignore=false and A contains missing data, the GeometricMean command will return undefined. If ignore=true all missing items in A will be ignored. The default value is false.

weights=Vector -- Data weights. The number of elements in the weights array must be equal to the number of elements in the original data sample. By default all elements in A are assigned weight 1.

Random Variable Options

The rv_options argument can contain one or more of the options shown below. More information for some options is available in the Statistics[RandomVariables] help page.

numeric=truefalse -- By default, the mean is computed using exact arithmetic. To compute the mean numerically, specify the numeric or numeric = true option.

Examples

>

withStatistics:

Compute the mean of the lognormal distribution with parameters p and q.

>

GeometricMeanLogNormalp,q

ⅇp

(1)

Use numeric parameters.

>

GeometricMeanLogNormal3,5

ⅇ3

(2)
>

GeometricMeanLogNormal3,5,numeric

20.08553690

(3)

Generate a random sample of size 1000 drawn from the above distribution and compute the sample mean.

>

YRandomVariableLogNormal3,5:

>

ASampleY,104:

>

GeometricMeanA

17.8358003133576

(4)

Compute the mean of a weighted data set.

>

Vseqi,i=57..77,undefined:

>

W2,4,14,41,83,169,394,669,990,1223,1329,1230,1063,646,392,202,79,32,16,5,2,5:

>

Digits40

Digits40

(5)
>

GeometricMeanV,weights=W

Floatundefined

(6)
>

GeometricMeanV,weights=W,ignore=true

66.97137432952068884182555875162767018341

(7)
>

Digits10:

Consider the following Matrix data set .

>

MMatrix3,1130,114694,4,1527,127368,3,907,88464,2,878,96484,4,995,128007

M31130114694415271273683907884642878964844995128007

(8)

We compute the geometric mean of each of the columns.

>

GeometricMeanM

3.103691147830721064.55590393367109802.271394999

(9)

References

Stuart, Alan, and Ord, Keith. Kendall's Advanced Theory of Statistics. 6th ed. London: Edward Arnold, 1998. Vol. 1: Distribution Theory.

Compatibility

The M parameter was introduced in Maple 16.

For more information on Maple 16 changes, see Updates in Maple 16 .


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