<?xml version="1.0" encoding="utf-8"?><!DOCTYPE article  PUBLIC '-//OASIS//DTD DocBook XML V4.4//EN'  'http://www.docbook.org/xml/4.4/docbookx.dtd'><article><articleinfo><title>FAQ/perc</title><revhistory><revision><revnumber>21</revnumber><date>2013-03-08 10:17:13</date><authorinitials>localhost</authorinitials><revremark>converted to 1.6 markup</revremark></revision><revision><revnumber>20</revnumber><date>2008-04-11 12:22:16</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>19</revnumber><date>2008-04-11 12:21:33</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>18</revnumber><date>2008-04-11 12:20:28</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>17</revnumber><date>2008-04-11 12:14:48</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>16</revnumber><date>2008-04-11 12:13:29</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>15</revnumber><date>2008-04-11 12:07:04</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>14</revnumber><date>2008-04-11 12:01:17</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>13</revnumber><date>2008-04-11 11:57:21</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>12</revnumber><date>2008-04-11 11:50:52</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>11</revnumber><date>2008-04-11 11:14:32</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>10</revnumber><date>2008-04-11 11:06:28</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>9</revnumber><date>2008-04-11 11:05:21</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>8</revnumber><date>2008-04-11 11:05:09</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>7</revnumber><date>2008-04-11 11:04:50</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>6</revnumber><date>2008-04-11 11:02:30</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>5</revnumber><date>2008-04-11 11:02:11</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>4</revnumber><date>2008-04-11 10:57:30</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>3</revnumber><date>2008-04-11 10:53:29</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>2</revnumber><date>2008-04-11 10:53:03</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>1</revnumber><date>2008-04-11 10:52:14</date><authorinitials>PeterWatson</authorinitials></revision></revhistory></articleinfo><section><title>How do I find out how many people have a score above a certain value?</title><para>Percentiles give the percentage of people who have a score below a threshold score. </para><para>Percentile (score) = 100 $$\frac{\mbox{n} \leq \mbox{score}}{\mbox{N}}$$ </para><para>100 - Percentile (score) = 100 $$\frac{\mbox{n} \gt \mbox{score}}{\mbox{N}}$$ </para><para>The score percentiles can be obtained by running the below in SPSS. </para><screen><![CDATA[FREQUENCIES VAR=SCORE.
EXE.]]></screen><para>or the below in R: </para><screen><![CDATA[score <- sort(score)
perc <- rep(-99,length(score))
ict <- 1
b <- duplicated(score)
for (ict in 1:length(score) {
for (i in score) {
perc[ict] <- 100*sum(score<=i)/length(score)
ict <- ict+1
}
 }
(percu <- perc[!duplicated(perc)])
(scoreu <- score[!duplicated(score)])
percu
scoreu]]></screen></section></article>