[R] Finding percentile of a value from an empirical distribution

[Robert A'gata]

Thank you. That's easier than I thought.

On Wed, Jan 11, 2012 at 12:06 AM, Jorge I Velez
<jorgeivanvelez at gmail.com> wrote:
> Hi Robert,
>
> Try
>
> set.seed(123)
> x <- seq(100)
> x <- sample(x, 1000, replace = TRUE)
> f <- ecdf(x)
> f(10)
> # [1] 0.099
> f(71)
> # [1] 0.716
>
> See ?ecdf for more information.
>
> HTH,
> Jorge.-
>
>
> On Tue, Jan 10, 2012 at 11:52 PM, Robert A'gata <> wrote:
>>
>> Hello,
>>
>> I am not sure how to do this in R. Any suggestion would be
>> appreciated. I have a vector of values from where I build an empirical
>> CDF. For example:
>>
>> > x <- seq(1,100)
>> > x <- sample(x,1000,replace=T)
>> > quantile(x,probs=seq(0,1,.05))
>>    0%     5%    10%    15%    20%    25%    30%    35%    40%    45%
>>  50%    55%
>>  1.00   5.00  10.00  16.00  20.00  25.00  31.00  36.00  41.00  45.55
>> 50.00  56.00
>>   60%    65%    70%    75%    80%    85%    90%    95%   100%
>>  60.00  65.00  70.00  74.00  80.00  85.00  91.00  95.05 100.00
>>
>> I would like to write a function that takes in a number z and vector x
>> (i.e. the raw vector).It returns percentile of z wrt x. E.g.
>>
>> > f(71,x)
>>
>> Should return something around 0.708 or 0.709. I am wondering if there
>> is any pre-packaged functions that do this in R? If not, how can I
>> write such a function. Any suggestion would be appreciated.
>>
>> Robert
>>
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>
>