<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0120-1751</journal-id>
<journal-title><![CDATA[Revista Colombiana de Estadística]]></journal-title>
<abbrev-journal-title><![CDATA[Rev.Colomb.Estad.]]></abbrev-journal-title>
<issn>0120-1751</issn>
<publisher>
<publisher-name><![CDATA[Departamento de Estadística - Universidad Nacional de Colombia.]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0120-17512011000100010</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Comparación de intervalos de confianza para la función de supervivencia con censura a derecha]]></article-title>
<article-title xml:lang="en"><![CDATA[Comparison of Confidence Intervals for the Survival Function in the Presence of Right Censoring]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[RAMÍREZ]]></surname>
<given-names><![CDATA[JAVIER]]></given-names>
</name>
<xref ref-type="aff" rid="A01"/>
</contrib>
</contrib-group>
<aff id="A01">
<institution><![CDATA[,Universidad de Córdoba Facultad de Ciencias Básicas Departamento de Matemáticas y Estadística]]></institution>
<addr-line><![CDATA[Montería ]]></addr-line>
<country>Colombia</country>
</aff>
<pub-date pub-type="pub">
<day>15</day>
<month>06</month>
<year>2011</year>
</pub-date>
<pub-date pub-type="epub">
<day>15</day>
<month>06</month>
<year>2011</year>
</pub-date>
<volume>34</volume>
<numero>1</numero>
<fpage>197</fpage>
<lpage>209</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_arttext&amp;pid=S0120-17512011000100010&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_abstract&amp;pid=S0120-17512011000100010&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.co/scielo.php?script=sci_pdf&amp;pid=S0120-17512011000100010&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[En este trabajo se comparan métodos para encontrar intervalos de confianza para la función de supervivencia, como los métodos de remuestreo Bootstrap aplicado a los estimadores de Kaplan-Meier y Nelson-Aalen. También, mediante las transformaciones \log, \log(-\log) y \arcsen que pueden resultar en muchos casos más efectivos. Además, se muestra el comportamiento que presentan los intervalos de confianza no paramétricos frente a los paramétricos.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[This work compares methods to find confidence interval for the survival function such as the resampling methods Bootstrap, applied to the Kaplan-Meier and Nelson-Aalen estimators. Also through \log, \log(-\log) and arcsin transformations that can result more effectives in many cases. The behavior of nonparametric confidence intervals against parametric ones is also shown.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[bootstrap]]></kwd>
<kwd lng="es"><![CDATA[censura a derecha]]></kwd>
<kwd lng="es"><![CDATA[estimador Kaplan-Meier]]></kwd>
<kwd lng="es"><![CDATA[función de supervivencia]]></kwd>
<kwd lng="es"><![CDATA[intervalos de confianza]]></kwd>
<kwd lng="en"><![CDATA[Bootstrap]]></kwd>
<kwd lng="en"><![CDATA[Confidence intervals]]></kwd>
<kwd lng="en"><![CDATA[Kaplan-Meier estimator]]></kwd>
<kwd lng="en"><![CDATA[Survival function]]></kwd>
<kwd lng="en"><![CDATA[Right censoring]]></kwd>
</kwd-group>
</article-meta>
</front><body><![CDATA[ 
<font size="2" face="verdana">

    <p>
<b>
<font size="4">
    <center>
Comparaci&oacute;n de intervalos de confianza para la funci&oacute;n de supervivencia con censura a derecha
</center>
</font>
</b>
</p>

    <p>
<b>
<font size="3">
    <center>
Comparison of Confidence Intervals for the Survival Function in the Presence of Right Censoring
</center>
</font>
</b>
</p>

    <p>
    <center>
JAVIER RAM&Iacute;REZ<sup>1</sup>
</center>
</p>

    <p>
<sup>1</sup>Universidad de C&oacute;rdoba, Facultad de Ciencias B&aacute;sicas, Departamento de Matem&aacute;ticas y Estad&iacute;stica, Monter&iacute;a, Colombia. Profesor asistente. Email: <a href="mailto:javierramirez@sinu.unicordoba.edu.co">javierramirez@sinu.unicordoba.edu.co</a>
    <br>
</p>

<hr size="1">

    <p>
<b>
    ]]></body>
<body><![CDATA[<center>
Resumen
</center>
</b>
</p>

    <p>
En este trabajo se comparan m&eacute;todos para encontrar intervalos de confianza para la funci&oacute;n de supervivencia, como los m&eacute;todos de remuestreo Bootstrap aplicado a los estimadores de Kaplan-Meier y Nelson-Aalen. Tambi&eacute;n, mediante las transformaciones \log, \log(-\log) y \arcsen que pueden resultar en muchos casos m&aacute;s efectivos. Adem&aacute;s, se muestra el comportamiento que presentan los intervalos de confianza no param&eacute;tricos frente a los param&eacute;tricos.
</p>

    <p>
<b>
Palabras clave:
</b>
bootstrap,
censura a derecha,
estimador Kaplan-Meier,
funci&oacute;n de supervivencia,
intervalos de confianza.
</p>

<hr size="1">

    <p>
<b>
    <center>
Abstract
</center>
</b>
</p>

    <p>
This work compares methods to find confidence interval for the survival function such as the resampling methods Bootstrap, applied to the Kaplan-Meier and Nelson-Aalen estimators. Also through \log, \log(-\log) and arcsin transformations that can result more effectives in many cases. The behavior of nonparametric confidence intervals against parametric ones is also shown.
</p>

    <p>
<b>
Key words:
</b>
Bootstrap,
Confidence intervals,
Kaplan-Meier estimator,
Survival function,
Right censoring.
</p>

<hr size="1">

    <p>
Texto completo disponible en <a href="pdf/rce/v34n1/v34n1a10.pdf">PDF</a>
</p>

<hr size="1">

    <p>
<b>
<font size="3">
Referencias
</font>
</b>
</p>


    <!-- ref --><p>
1. Aalen, O. & Johansen, S. (1978), `An empirical transition matrix for nonhomogeneus Markov chains based on censored observations´, <i>Scandinavian Journal of Statistics</i> <b>5</b>(3), 141-150.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000022&pid=S0120-1751201100010001000001&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p>
2. Akritas, M. (1986), `Bootstrapping the Kaplan-Meier estimator´, <i>American Statistical Association</i> <b>81</b>(396), 1032-1038.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000023&pid=S0120-1751201100010001000002&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p>
3. Anderson, J., Bernstein, L. & Pike, M. (1982), `Confidence intervals for probabilities of survival and quantiles in life-table analysis´, <i>Biometrics</i> <b>38</b>(2), 407-416.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000024&pid=S0120-1751201100010001000003&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p>
4. Borgan, \O & Liest\ol, K. (1990), `A note on confidence intervals and bands for the survival function based on transformations´, <i>Scandinavian Journal of Statistics</i> <b>17</b>(1), 35-41.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000025&pid=S0120-1751201100010001000004&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p>
5. Correa, J. & Sierra, E. (2003), `Intervalos de confianza para la comparaci\&#39;on de dos proporciones´, <i>Revista Colombiana de Estad\&#39;\istica</i> <b>26</b>(1), 61-75.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000026&pid=S0120-1751201100010001000005&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p>
6. Greenwood, M. (1926), `The natural duration of cancer´, <i>Reports on Public Health and Medical Subjects</i>(33), 1-26.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000027&pid=S0120-1751201100010001000006&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p>
7. Kalbfleisch, J. & Prentice, R. (1980), <i>The Statistical Analysis of Failure Time Data</i>, Wiley, New York, United States.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000028&pid=S0120-1751201100010001000007&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p>
8. Kaplan, E. & Meier, P. (1958), `Estimation from incomplete observations´, <i>American Statistical Association</i> <b>53</b>(282), 457-481.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000029&pid=S0120-1751201100010001000008&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p>
9. Nair, V. (1984), `Confidence bands for survival functions with censored data´, <i>Technometrics</i> <b>26</b>(3), 265-275.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000030&pid=S0120-1751201100010001000009&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p>
10. Nelson, W. (1969), `Hazard plotting for incomplete failure data´, <i>Journal of Quality Technology</i> <b>61</b>(1), 27-52.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000031&pid=S0120-1751201100010001000010&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><!-- ref --><p>
11. R Development Core Team, (2008), <i>R: A Language and Environment for Statistical Computing</i>, R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0.
*<a href="http://www.R-project.org">http://www.R-project.org</a>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[&#160;<a href="javascript:void(0);" onclick="javascript: window.open('/scielo.php?script=sci_nlinks&ref=000032&pid=S0120-1751201100010001000011&lng=','','width=640,height=500,resizable=yes,scrollbars=1,menubar=yes,');">Links</a>&#160;]<!-- end-ref --><center>
<b>&#91;Recibido en septiembre de 2010. Aceptado en marzo de 2011&#93;</b>
</center>
<hr size="1">

    <p>
Este art&iacute;culo se puede citar en <i>LaTeX</i> utilizando la siguiente referencia bibliogr&aacute;fica de <i>BibTeX</i>:
</p>
<code><font size="2">@ARTICLE{RCEv34n1a10,    <br>
 &nbsp;&nbsp;&nbsp; AUTHOR &nbsp;= {Ram&iacute;rez, Javier},    <br>
 &nbsp;&nbsp;&nbsp; TITLE &nbsp; = {{Comparaci&oacute;n de intervalos de confianza para la funci&oacute;n de supervivencia con censura a derecha}},    <br>
 &nbsp;&nbsp;&nbsp; JOURNAL = {Revista Colombiana de Estad&iacute;stica},    <br>
&nbsp;&nbsp;&nbsp; YEAR &nbsp;&nbsp; = {2011},    <br>
&nbsp;&nbsp;&nbsp; volume &nbsp;= {34},    <br>
&nbsp;&nbsp;&nbsp; number &nbsp;= {1},    <br>
&nbsp;&nbsp;&nbsp; pages &nbsp; = {197-209}    <br>
}</font></code>

<hr size="1">
</font>
    ]]></body>
<body><![CDATA[ ]]></body><back>
<ref-list>
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<label>1</label><nlm-citation citation-type="journal">
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<article-title xml:lang="en"><![CDATA[`An empirical transition matrix for nonhomogeneus Markov chains based on censored observations´]]></article-title>
<source><![CDATA[Scandinavian Journal of Statistics]]></source>
<year>1978</year>
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