<?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>2448-9190</journal-id>
<journal-title><![CDATA[Revista alergia México]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. alerg. Méx.]]></abbrev-journal-title>
<issn>2448-9190</issn>
<publisher>
<publisher-name><![CDATA[Colegio Mexicano de Inmunología Clínica y Alergia A.C.]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S2448-91902017000200220</article-id>
<article-id pub-id-type="doi">10.29262/ram.v64i2.267</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[El protocolo de investigación V: el cálculo del tamaño de muestra]]></article-title>
<article-title xml:lang="en"><![CDATA[The research protocol V: The calculation of sample size]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Rendón-Macías]]></surname>
<given-names><![CDATA[Mario Enrique]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Villasís-Keever]]></surname>
<given-names><![CDATA[Miguel Ángel]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Instituto Mexicano del Seguro Social Centro Médico Nacional Siglo XXI Hospital de Pediatría]]></institution>
<addr-line><![CDATA[Ciudad de México ]]></addr-line>
<country>Mexico</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>06</month>
<year>2017</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>06</month>
<year>2017</year>
</pub-date>
<volume>64</volume>
<numero>2</numero>
<fpage>220</fpage>
<lpage>227</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S2448-91902017000200220&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S2448-91902017000200220&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S2448-91902017000200220&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen: El tamaño de la muestra se refiere al número de participantes que se incluirá en un estudio de investigación. Si se realiza adecuadamente el cálculo, no solamente se establecerán conclusiones con sustento estadístico y se limitarán los riesgos potenciales a los sujetos incluidos en la investigación, sino que además el estudio podrá planearse adecuadamente para optimizar costos económicos y tiempo. Para el cálculo del tamaño de la muestra se requiere información que debe estar sustentada en el protocolo de investigación; dicha información incluye que los objetivos (estudio descriptivo o para establecer diferencias), hipótesis (con magnitud y dirección) y escala de medición de la o las variables de desenlace estén bien planteadas, así como tener considerados los errores tipos I y II. En esta revisión se describe los requerimientos necesarios para el cálculo del tamaño de la muestra, incluyendo ejemplos en diseños de investigación clínica.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract: Sample size refers to the number of participants to be included in a research study. If the calculation is carried out properly, not only conclusions will be established with statistical support and the potential risks to the subjects included in the investigation will be limited, but also the study can be properly planned to optimize economic and time costs. Calculation of sample size requires information that must be supported by the research protocol. This information includes that the objectives (descriptive study or a study to establish differences between groups) and hypotheses are well elaborated (with magnitude and direction), the scale of measurement of the outcome variable(s) must be defined, and type I error and type II error appropriately identified. This review describes how to specify the requirements needed for sample size calculation, including examples in clinical research designs.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Investigación]]></kwd>
<kwd lng="es"><![CDATA[Mediciones, métodos y teorías]]></kwd>
<kwd lng="es"><![CDATA[Tamaño de la muestra]]></kwd>
<kwd lng="en"><![CDATA[Research]]></kwd>
<kwd lng="en"><![CDATA[Measurements, methods and theories]]></kwd>
<kwd lng="en"><![CDATA[Sample size]]></kwd>
</kwd-group>
</article-meta>
</front><back>
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