Wilks¶
- class Wilks(*args)¶
Class to estimate a confidence interval on a quantile.
Refer to Estimation of a quantile upper bound by Wilks’ method.
- Parameters:
- X
RandomVector
, A random vector of dimension 1.
- X
Methods
ComputeSampleSize
(quantileLevel, confidenceLevel)Evaluate the minimum size of the sample.
computeQuantileBound
(quantileLevel, ...[, ...])Evaluate an upper bound of a quantile.
Notes
This static class estimates an upper bound of the quantile of level of the random variable with a confidence greater than , using a given order statistics.
Let be the unknown quantile of level of the random variable of dimension 1. Let be a sample of independent and identically distributed variables according to . Let be the -th order statistics of which means that is the -th maximum of for . For example, is the minimum and is the maximum. We have:
Given , and , the class estimates the minimal size such that:
Once the minimal size has been estimated, a sample of size can be generated from and an upper bound of is estimated by the value of the on the sample.
- __init__(*args)¶
- static ComputeSampleSize(quantileLevel, confidenceLevel, marginIndex=0)¶
Evaluate the minimum size of the sample.
- Parameters:
- alphapositive float in
The level of the quantile.
- betapositive float in ,
The confidence level on the upper bound.
- iint
The index such that is an upper bound of with confidence . Default value is .
- Returns:
- nint,
The minimum size of the sample.
Notes
The minimum sample size is such that:
- computeQuantileBound(quantileLevel, confidenceLevel, marginIndex=0)¶
Evaluate an upper bound of a quantile.
- Parameters:
- alphapositive float in
The level of the quantile.
- betapositive float in
The confidence level on the upper bound.
- iint
The index such that is an upper bound of with confidence level . Default value is .
- Returns:
- upperBound
Point
The estimate of the quantile upper bound.
- upperBound
Notes
The method starts by evaluating the minimum sample size such that:
Then, it generates a sample of size from the random vector . The upper bound of is , that is, the -th observation in the ordered sample.
Examples using the class¶
Estimate a confidence interval of a quantile