Description Usage Arguments Details Value Author(s) References See Also Examples
Calculates bootstrapped S-estimates using the Fast and Robust Bootstrap method.
1 | Sboot_loccov(Y, R = 999, ests = Sest_loccov(Y))
|
Y |
matrix or data frame. |
R |
number of bootstrap samples. Default is |
ests |
original S-estimates as returned by |
This function is called by FRBpcaS
and FRBhotellingS
, it is typically not to be used on its own.
It requires the S-estimates of multivariate location and scatter/shape
(the result of Sest_loccov
applied on Y
), supplied through the argument ests
.
If ests
is not provided, Sest_loccov
calls the implementation of the multivariate S-estimates in package rrcov of Todorov and Filzmoser (2009) with default arguments.
For multivariate data the fast and robust bootstrap was developed by Salibian-Barrera, Van Aelst and Willems (2006).
The value centered
gives a matrix with R
columns and p+p*p rows (p is the number of variables in Y
),
containing the recalculated estimates of the S-location and -covariance. Each column represents a different bootstrap sample.
The first p rows are the location estimates and the next p*p rows are the covariance estimates (vectorized). The estimates
are centered by the original estimates, which are also returned through Sest
.
A list containing:
centered |
recalculated estimates of location and covariance (centered by original estimates) |
Sest |
original estimates of location and covariance |
Gert Willems, Ella Roelant and Stefan Van Aelst
M. Salibian-Barrera, S. Van Aelst and G. Willems (2006) PCA based on multivariate MM-estimators with fast and robust bootstrap. Journal of the American Statistical Association, 101, 1198–1211.
M. Salibian-Barrera, S. Van Aelst and G. Willems (2008) Fast and robust bootstrap. Statistical Methods and Applications, 17, 41–71.
V. Todorov and P. Filzmoser (2009) An object-oriented framework for robust multivariate analysis. Journal of Statistical Software, 32, 1–47. URL http://www.jstatsoft.org/v32/i03/.
S. Van Aelst and G. Willems (2013). Fast and robust bootstrap for multivariate inference: The R package FRB. Journal of Statistical Software, 53(3), 1–32. URL: http://www.jstatsoft.org/v53/i03/.
FRBpcaS
, FRBhotellingS
, MMboot_loccov
1 2 3 | Y <- matrix(rnorm(50*5), ncol=5)
Sests <- Sest_loccov(Y, bdp = 0.25)
bootresult <- Sboot_loccov(Y, R = 1000, ests = Sests)
|
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