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seminars:stat:04162015 [2015/04/15 12:24] qiaoseminars:stat:04162015 [2015/04/15 12:25] (current) qiao
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 +<WRAP centeralign>##Statistics Seminar##\\ Department of Mathematical Sciences</WRAP>
 +
 +~~META:title =April 16, 2015~~
 +<WRAP 70% center>
 +^  **DATE:**|Thursday, April 16, 2015 |
 +^  **TIME:**|1:15pm to 2:15pm |
 +^  **LOCATION:**|WH 100E |
 +^  **SPEAKER:**|Ruiqi Liu (Binghamton University) |
 +^  **TITLE:**|Density estimation for power transformations—Paper Discussion |
 +</WRAP>
 +\\
 +
 +<WRAP center box 80%>
 +<WRAP centeralign>**Abstract**</WRAP>
 +I will discuss a paper of Olga Y. Savchuk and Anton Schick.
 +Consider a random sample $X_1,...,X_n$ from a density $f$. For a positive $\alpha$,
 +the density $g$ of $t(X_1) = |X_1|^\alpha sign(X_1)$ can be estimated in two ways: by a
 +kernel estimator based on the transformed data $t(X_1),...,t(X_n)$ or by a plug-
 +in estimator transformed from a kernel estimator based on the original data.
 +In this paper, they compare the performance of these two estimators using
 +MSE and MISE. For MSE, the plug-in estimator is better in the case $\alpha > 1$
 +when $f$ is symmetric and unimodal, and in the case $\alpha \ge 2.5$ when $f$ is right-
 +skewed and/or bimodal. For $\alpha < 1$, the plug-in estimator performs better
 +around the modes of $g$, while the transformed data estimator is better in the
 +tails of $g$. For global comparison MISE, the plug-in estimator has a faster
 +rate of convergence for $0.4 \le \alpha < 1$ and $1 < \alpha < 2$. For $\alpha < 0.4$, the plug-in
 +estimator is preferable for a symmetric density $f$ with exponentially decaying
 +tails, while the transformed data estimator has a better performance when
 +$f$ is right-skewed or heavy-tailed. Applications to real and simulated data
 +illustrated these theoretical findings.
 +</WRAP>