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| Percentile (score) = 100$$\frac{n \leq score}{N}$$ | Percentile (score) = 100 $$\frac{\mbox{n} \leq \mbox{score}}{\mbox{N}}$$ |
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| 1 - Percentile (score) = 100$$\frac{n \gt score}{N}$$ | 100 - Percentile (score) = 100 $$\frac{\mbox{n} \gt \mbox{score}}{\mbox{N}}$$ |
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| In R the percentages of people with scores equal or below each observed score can be obtained by running {{{ perc <- rep(-99,length(score)) a <- rep(-99,length(score)) ict <- 1 b <- duplicated(score) for (i in score) { perc[i] <- 100*sum(score<=i)/length(score) ict <- ict+1 if (b[i] == FALSE) { a[i] <- score[ict] } } perc a }}} |
How do I find out how many people have a score above a certain value?
Percentiles give the percentage of people who have a score below a threshold score.
Percentile (score) = 100 $$\frac{\mbox{n} \leq \mbox{score}}{\mbox{N}}$$
100 - Percentile (score) = 100 $$\frac{\mbox{n} \gt \mbox{score}}{\mbox{N}}$$
The percentiles for each score are routinely outputted using the frequency procedure in SPSS.
FREQUENCIES VAR=SCORE. EXE.
In R the percentages of people with scores equal or below each observed score can be obtained by running
perc <- rep(-99,length(score))
a <- rep(-99,length(score))
ict <- 1
b <- duplicated(score)
for (i in score) {
perc[i] <- 100*sum(score<=i)/length(score)
ict <- ict+1
if (b[i] == FALSE) {
a[i] <- score[ict]
}
}
perc
a