ReIns: cQuant – R documentation

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cQuant

Estimator of large quantiles using censored Hill

Description

Computes estimates of large quantiles Q(1-p) using the estimates for the EVI obtained from the Hill estimator adapted for right censoring.

Usage

cQuant(data, censored, gamma1, p, plot = FALSE, add = FALSE, 
       main = "Estimates of extreme quantile", ...)

Arguments

`data`	Vector of n observations.
`censored`	A logical vector of length n indicating if an observation is censored.
`gamma1`	Vector of n-1 estimates for the EVI obtained from `cHill`.
`p`	The exceedance probability of the quantile (we estimate Q(1-p) for p small).
`plot`	Logical indicating if the estimates should be plotted as a function of k, default is `FALSE`.
`add`	Logical indicating if the estimates should be added to an existing plot, default is `FALSE`.
`main`	Title for the plot, default is `"Estimates of extreme quantile"`.
`...`	Additional arguments for the `plot` function, see `plot` for more details.

Details

The quantile is estimated as

\hat{Q}(1-p)=Z_{n-k,n} \times ( (1-km)/p)^{H_{k,n}^c}

with Z_{i,n} the i-th order statistic of the data, H_{k,n}^c the Hill estimator adapted for right censoring and km the Kaplan-Meier estimator for the CDF evaluated in Z_{n-k,n}.

Value

A list with following components:

`k`	Vector of the values of the tail parameter k.
`Q`	Vector of the corresponding quantile estimates.
`p`	The used exceedance probability.

Author(s)

Tom Reynkens.

References

Beirlant, J., Guillou, A., Dierckx, G. and Fils-Villetard, A. (2007). "Estimation of the Extreme Value Index and Extreme Quantiles Under Random Censoring." Extremes, 10, 151–174.

Examples

# Set seed
set.seed(29072016)

# Pareto random sample
X <- rpareto(500, shape=2)

# Censoring variable
Y <- rpareto(500, shape=1)

# Observed sample
Z <- pmin(X, Y)

# Censoring indicator
censored <- (X>Y)

# Hill estimator adapted for right censoring
chill <- cHill(Z, censored=censored, plot=TRUE)

# Large quantile
p <- 10^(-4)
cQuant(Z, gamma1=chill$gamma, censored=censored, p=p, plot=TRUE)

ReIns

Functions from "Reinsurance: Actuarial and Statistical Aspects"

v1.0.10

GPL (>= 2)

Authors

Tom Reynkens [aut, cre] (<https://orcid.org/0000-0002-5516-5107>), Roel Verbelen [aut] (R code for Mixed Erlang distribution, <https://orcid.org/0000-0002-2347-9240>), Anastasios Bardoutsos [ctb] (Original R code for cEPD estimator), Dries Cornilly [ctb] (Original R code for EVT estimators for truncated data), Yuri Goegebeur [ctb] (Original S-Plus code for basic EVT estimators), Klaus Herrmann [ctb] (Original R code for GPD estimator)

Initial release

2020-05-16