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Question: Is it possible to instantiate all the attributes of a random variable?

Question:Is it possible to instantiate all the attributes of a random variable?

mmcdara 6149 Maple 2015
statistics distribution
August 05 2019
2

Hi, 

When creating a user random variable, I would like to instanciate some of its attributes, for instance ParentName.
But it seems that it's not always possible.

​​​​​​​Is it a Maple's limitation or am I not doing the things correctly ?
​​​​​​​
Example:
 

> 

restart:
> 

with(Statistics):
> 

U := RandomVariable(Uniform(0, 1)):
> 

interface(warnlevel=0):
> 

A := attributes(U)[3]

_ProbabilityDistribution

 (1)
> 

AllAttributes := with(A);

[CDF, Conditions, HodgesLehmann, InverseSurvivalFunction, MGF, MaximumLikelihoodEstimate, Mean, Median, Mode, PDF, Parameters, ParentName, Quantile, RandomSample, RandomSampleSetup, RandomVariate, RousseeuwCrouxSn, Support, Variance]

 (2)
> 

A:-ParentName

UniformDistribution

 (3)
> 

# Define a user random variable

v := Distribution(PDF = (z -> piecewise(0 <= t and t < 1, 1, 0))):
V := RandomVariable(v):
A := attributes(V)[3];
AllAttributes := with(A);
A:-Conditions;

_ProbabilityDistribution0

  

[Conditions, PDF]

  

[]

 (4)
> 

# its definition can be augmented by adding some recognized attributes...
# even if the result returned by Mean is strange

v := Distribution(PDF = (z -> piecewise(0 <= t and t < 1, 1, 0)), 'Mean'=1/Pi, 'Median'=exp(-1)):
V := RandomVariable(v):
A := attributes(V)[3];
AllAttributes := with(A);
[Median, Mean](V)

_ProbabilityDistribution1

  

[Conditions, Mean, Median, PDF]

  

[exp(-1), 1/Pi(_R1)]

 (5)
> 

# but not all the recognized attributes seem to be able to be instanciated:

v := Distribution(PDF = (z -> piecewise(a <= t and t < b, 1/(b-a), 0)), 'Parameters'=[a, b]);
v := Distribution(PDF = (z -> piecewise(a <= t and t < b, 1/(b-a), 0)), 'ParentNames'=MyDistribution);

Error, (in Statistics:-Distribution) invalid input: too many and/or wrong type of arguments passed to NewDistribution; first unused argument is Parameters = [a, b]

  

Error, (in Statistics:-Distribution) invalid input: too many and/or wrong type of arguments passed to NewDistribution; first unused argument is ParentNames = MyDistribution

  
> 

 

 


 

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