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ecdf

gawesh
Hi,
Newbie here. I read the R for Beginners but i still don't get this.

I have the following data (this is just an example) in a CSV file:

    courseid numstudents
        101         209
        141          13
        246         140
        263           8
        321          10
        361          10
        364          28
        365          25
        366          23
        367          34

I load my data using:

fs<-read.csv(file="C:\\num_students_inallmodules.csv",header=T, sep=',')

I want to get the ecdf. So, I looked at the ?ecdf which says usage:ecdf(x)

So I expected ecdf(fs$numstudents) to work

Instead it just returned:
Call: ecdf(fs$numstudents)
 x[1:210] =      1,      2,      3,  ...,   3717,   4538

After Googling, got this to work:
ecdf(fs$numstudents)(unique(fs$numstudents))

But I don't understand why if the ?ecdf says usage is ecdf(x) ... I
need to use ecdf(fs$numstudents)(unique(fs$numstudents)) to get this
to work?

Can somebody explain this to me?

Regards
Gawesh

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Re: ecdf

David Winsemius

On Oct 16, 2011, at 11:31 AM, gj wrote:

> Hi,
> Newbie here. I read the R for Beginners but i still don't get this.
>
> I have the following data (this is just an example) in a CSV file:
>
>    courseid numstudents
>        101         209
>        141          13
>        246         140
>        263           8
>        321          10
>        361          10
>        364          28
>        365          25
>        366          23
>        367          34
>
> I load my data using:
>
> fs<-read.csv(file="C:\\num_students_inallmodules.csv",header=T,  
> sep=',')
>
> I want to get the ecdf. So, I looked at the ?ecdf which says  
> usage:ecdf(x)
>
> So I expected ecdf(fs$numstudents) to work
>
> Instead it just returned:
> Call: ecdf(fs$numstudents)
> x[1:210] =      1,      2,      3,  ...,   3717,   4538
>
> After Googling, got this to work:
> ecdf(fs$numstudents)(unique(fs$numstudents))
>
> But I don't understand why if the ?ecdf says usage is ecdf(x) ... I
> need to use ecdf(fs$numstudents)(unique(fs$numstudents)) to get this
> to work?
>
> Can somebody explain this to me?

ecdf() returns a function rather than a vector. You need to supply  
arguments to that function to get something that you recognize.

Had you passed that function off to plot you would have seen that the  
information needed to calculate the plot is obviously "in there". If  
you go to the stepfun page you find that the knots function can  
recover some of htat information for display.

 > plot( ecdf(fs$numstudents) )
 > knots( ecdf(fs$numstudents) )
[1]   8  10  13  23  25  28  34 140 209

If you count the knots you can deduce the quantile values (the "y-
values")  at which those "x-values" will start the step "dot-line"
--

David Winsemius, MD
West Hartford, CT

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Re: ecdf

djmuseR
In reply to this post by gawesh
Hi:

I don't understand what you're attempting to do. Wouldn't courseid be
a categorical variable with a numeric label? If that is so, why are
you trying to compute an EDF? An EDF computes cumulative relative
frequency of a random variable, which by definition is numeric. If we
were talking about EDFs for a distribution of student course grades on
a numeric point system by course, that would make some sense, but I
don't see how the course IDs themselves qualify as being on an
interval scale of measurement. Could you clarify your intent?

Dennis

On Sun, Oct 16, 2011 at 8:31 AM, gj <[hidden email]> wrote:

> Hi,
> Newbie here. I read the R for Beginners but i still don't get this.
>
> I have the following data (this is just an example) in a CSV file:
>
>    courseid numstudents
>        101         209
>        141          13
>        246         140
>        263           8
>        321          10
>        361          10
>        364          28
>        365          25
>        366          23
>        367          34
>
> I load my data using:
>
> fs<-read.csv(file="C:\\num_students_inallmodules.csv",header=T, sep=',')
>
> I want to get the ecdf. So, I looked at the ?ecdf which says usage:ecdf(x)
>
> So I expected ecdf(fs$numstudents) to work
>
> Instead it just returned:
> Call: ecdf(fs$numstudents)
>  x[1:210] =      1,      2,      3,  ...,   3717,   4538
>
> After Googling, got this to work:
> ecdf(fs$numstudents)(unique(fs$numstudents))
>
> But I don't understand why if the ?ecdf says usage is ecdf(x) ... I
> need to use ecdf(fs$numstudents)(unique(fs$numstudents)) to get this
> to work?
>
> Can somebody explain this to me?
>
> Regards
> Gawesh
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

______________________________________________
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https://stat.ethz.ch/mailman/listinfo/r-help
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Re: ecdf

David Winsemius

On Oct 16, 2011, at 3:53 PM, Dennis Murphy wrote:

> Hi:
>
> I don't understand what you're attempting to do. Wouldn't courseid be
> a categorical variable with a numeric label? If that is so, why are
> you trying to compute an EDF? An EDF computes cumulative relative
> frequency of a random variable, which by definition is numeric. If we
> were talking about EDFs for a distribution of student course grades on
> a numeric point system by course, that would make some sense, but I
> don't see how the course IDs themselves qualify as being on an
> interval scale of measurement. Could you clarify your intent?

Huh? gawesh asked for ecdf on numstrudents (not courseid)  ... pretty  
clearly a numeric value for which an ECDF should make sense.

--
David.

--

> Dennis
>
> On Sun, Oct 16, 2011 at 8:31 AM, gj <[hidden email]> wrote:
>> Hi,
>> Newbie here. I read the R for Beginners but i still don't get this.
>>
>> I have the following data (this is just an example) in a CSV file:
>>
>>    courseid numstudents
>>        101         209
>>        141          13
>>        246         140
>>        263           8
>>        321          10
>>        361          10
>>        364          28
>>        365          25
>>        366          23
>>        367          34
>>
>> I load my data using:
>>
>> fs<-read.csv(file="C:\\num_students_inallmodules.csv",header=T,  
>> sep=',')
>>
>> I want to get the ecdf. So, I looked at the ?ecdf which says  
>> usage:ecdf(x)
>>
>> So I expected ecdf(fs$numstudents) to work
>>
>> Instead it just returned:
>> Call: ecdf(fs$numstudents)
>>  x[1:210] =      1,      2,      3,  ...,   3717,   4538
>>
>> After Googling, got this to work:
>> ecdf(fs$numstudents)(unique(fs$numstudents))
>>
>> But I don't understand why if the ?ecdf says usage is ecdf(x) ... I
>> need to use ecdf(fs$numstudents)(unique(fs$numstudents)) to get this
>> to work?
>>
>> Can somebody explain this to me?
>>
>> Regards
>> Gawesh
>>
>> ______________________________________________
>> [hidden email] mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

David Winsemius, MD
Heritage Laboratories
West Hartford, CT

______________________________________________
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Re: ecdf

gawesh
David is right. I am looking for the ecfd for fs$numstudents. The
other column is just an id.

I guess I don't know how to read the R documentation when it comes to functions.

looking at the documentation, i now notice that it says "Compute an
empirical cummulative distribution function and not a vector.

But still I would had assumed that in ecdf(x) ... the x is the argument.

So ecdf(fs$numstudents)(unique(fs$numstudents))
     ===============  ==================
          function                       arguments

Yes? But I can't read that from the documentation? I suspect it has
something to those dots .... in the arguments which I don't
understand.

Why it says usage ecdf(x) when it's clearly not the case?

I don't get it.

Gawesh


On Sun, Oct 16, 2011 at 11:02 PM, David Winsemius
<[hidden email]> wrote:

>
> On Oct 16, 2011, at 3:53 PM, Dennis Murphy wrote:
>
>> Hi:
>>
>> I don't understand what you're attempting to do. Wouldn't courseid be
>> a categorical variable with a numeric label? If that is so, why are
>> you trying to compute an EDF? An EDF computes cumulative relative
>> frequency of a random variable, which by definition is numeric. If we
>> were talking about EDFs for a distribution of student course grades on
>> a numeric point system by course, that would make some sense, but I
>> don't see how the course IDs themselves qualify as being on an
>> interval scale of measurement. Could you clarify your intent?
>
> Huh? gawesh asked for ecdf on numstrudents (not courseid)  ... pretty
> clearly a numeric value for which an ECDF should make sense.
>
> --
> David.
>
> --
>>
>> Dennis
>>
>> On Sun, Oct 16, 2011 at 8:31 AM, gj <[hidden email]> wrote:
>>>
>>> Hi,
>>> Newbie here. I read the R for Beginners but i still don't get this.
>>>
>>> I have the following data (this is just an example) in a CSV file:
>>>
>>>   courseid numstudents
>>>       101         209
>>>       141          13
>>>       246         140
>>>       263           8
>>>       321          10
>>>       361          10
>>>       364          28
>>>       365          25
>>>       366          23
>>>       367          34
>>>
>>> I load my data using:
>>>
>>> fs<-read.csv(file="C:\\num_students_inallmodules.csv",header=T, sep=',')
>>>
>>> I want to get the ecdf. So, I looked at the ?ecdf which says
>>> usage:ecdf(x)
>>>
>>> So I expected ecdf(fs$numstudents) to work
>>>
>>> Instead it just returned:
>>> Call: ecdf(fs$numstudents)
>>>  x[1:210] =      1,      2,      3,  ...,   3717,   4538
>>>
>>> After Googling, got this to work:
>>> ecdf(fs$numstudents)(unique(fs$numstudents))
>>>
>>> But I don't understand why if the ?ecdf says usage is ecdf(x) ... I
>>> need to use ecdf(fs$numstudents)(unique(fs$numstudents)) to get this
>>> to work?
>>>
>>> Can somebody explain this to me?
>>>
>>> Regards
>>> Gawesh
>>>
>>> ______________________________________________
>>> [hidden email] mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>
>> ______________________________________________
>> [hidden email] mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
> David Winsemius, MD
> Heritage Laboratories
> West Hartford, CT
>
>

______________________________________________
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https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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Re: ecdf

Sarah Goslee
Hi,

On Sun, Oct 16, 2011 at 8:48 PM, gj <[hidden email]> wrote:
> David is right. I am looking for the ecfd for fs$numstudents. The
> other column is just an id.
>
> I guess I don't know how to read the R documentation when it comes to functions.
>
> looking at the documentation, i now notice that it says "Compute an
> empirical cumulative distribution function and not a vector.
>
> But still I would had assumed that in ecdf(x) ... the x is the argument.

ecdf() is the function you're calling.
x is your vector, for which you want the ECDF.

num.ecdf <- ecdf(fs$numstudents)

There. That's the ECDF.

But the ECDF is a *function* - that's what the F stands for, after all.

If you're looking for the percentiles for your data, you might try:

num.ecdf(fs$numstudents)

You might also try working the examples given in ?ecdf yourself, so
that you can see exactly what's going on before you try it with your
own data.


> So ecdf(fs$numstudents)(unique(fs$numstudents))
>     ===============  ==================
>          function                       arguments
>
> Yes? But I can't read that from the documentation? I suspect it has
> something to those dots .... in the arguments which I don't
> understand.

Yes.

That's the condensed version of what I just proposed, done in
one step, instead of two. The two-step version is definitely in
the help. It doesn't have anything to do with the ..., which simply allow
for other arguments to be passed.

> Why it says usage ecdf(x) when it's clearly not the case?
>
> I don't get it.

Clearly that is the case. ecdf(x) returns the empirical cumulative
distribution *function* of the vector of data x.

I'm not entirely sure what you think you should be getting. Perhaps
if you explained your expectations, the list would be able to help
you achieve them.

Sarah

> Gawesh
>
>
> On Sun, Oct 16, 2011 at 11:02 PM, David Winsemius
> <[hidden email]> wrote:
>>
>> On Oct 16, 2011, at 3:53 PM, Dennis Murphy wrote:
>>
>>> Hi:
>>>
>>> I don't understand what you're attempting to do. Wouldn't courseid be
>>> a categorical variable with a numeric label? If that is so, why are
>>> you trying to compute an EDF? An EDF computes cumulative relative
>>> frequency of a random variable, which by definition is numeric. If we
>>> were talking about EDFs for a distribution of student course grades on
>>> a numeric point system by course, that would make some sense, but I
>>> don't see how the course IDs themselves qualify as being on an
>>> interval scale of measurement. Could you clarify your intent?
>>
>> Huh? gawesh asked for ecdf on numstrudents (not courseid)  ... pretty
>> clearly a numeric value for which an ECDF should make sense.
>>
>> --
>> David.
>>
>> --
>>>
>>> Dennis
>>>
>>> On Sun, Oct 16, 2011 at 8:31 AM, gj <[hidden email]> wrote:
>>>>
>>>> Hi,
>>>> Newbie here. I read the R for Beginners but i still don't get this.
>>>>
>>>> I have the following data (this is just an example) in a CSV file:
>>>>
>>>>   courseid numstudents
>>>>       101         209
>>>>       141          13
>>>>       246         140
>>>>       263           8
>>>>       321          10
>>>>       361          10
>>>>       364          28
>>>>       365          25
>>>>       366          23
>>>>       367          34
>>>>
>>>> I load my data using:
>>>>
>>>> fs<-read.csv(file="C:\\num_students_inallmodules.csv",header=T, sep=',')
>>>>
>>>> I want to get the ecdf. So, I looked at the ?ecdf which says
>>>> usage:ecdf(x)
>>>>
>>>> So I expected ecdf(fs$numstudents) to work
>>>>
>>>> Instead it just returned:
>>>> Call: ecdf(fs$numstudents)
>>>>  x[1:210] =      1,      2,      3,  ...,   3717,   4538
>>>>
>>>> After Googling, got this to work:
>>>> ecdf(fs$numstudents)(unique(fs$numstudents))
>>>>
>>>> But I don't understand why if the ?ecdf says usage is ecdf(x) ... I
>>>> need to use ecdf(fs$numstudents)(unique(fs$numstudents)) to get this
>>>> to work?
>>>>
>>>> Can somebody explain this to me?
>>>>
>>>> Regards
>>>> Gawesh
>>>>
>>>> ______________________________________________
>>>> [hidden email] mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>> PLEASE do read the posting guide
>>>> http://www.R-project.org/posting-guide.html
>>>> and provide commented, minimal, self-contained, reproducible code.
>>>>
>>>
>>> ______________________________________________
>>> [hidden email] mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>
>> David Winsemius, MD
>> Heritage Laboratories
>> West Hartford, CT
>>
>>
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>



--
Sarah Goslee
http://www.stringpage.com
http://www.sarahgoslee.com
http://www.functionaldiversity.org

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Re: ecdf

djmuseR
In reply to this post by gawesh
Thanks for the clarification. I stand corrected.

Dennis

On Sun, Oct 16, 2011 at 5:48 PM, gj <[hidden email]> wrote:

> David is right. I am looking for the ecfd for fs$numstudents. The
> other column is just an id.
>
> I guess I don't know how to read the R documentation when it comes to functions.
>
> looking at the documentation, i now notice that it says "Compute an
> empirical cummulative distribution function and not a vector.
>
> But still I would had assumed that in ecdf(x) ... the x is the argument.
>
> So ecdf(fs$numstudents)(unique(fs$numstudents))
>     ===============  ==================
>          function                       arguments
>
> Yes? But I can't read that from the documentation? I suspect it has
> something to those dots .... in the arguments which I don't
> understand.
>
> Why it says usage ecdf(x) when it's clearly not the case?
>
> I don't get it.
>
> Gawesh
>
>
> On Sun, Oct 16, 2011 at 11:02 PM, David Winsemius
> <[hidden email]> wrote:
>>
>> On Oct 16, 2011, at 3:53 PM, Dennis Murphy wrote:
>>
>>> Hi:
>>>
>>> I don't understand what you're attempting to do. Wouldn't courseid be
>>> a categorical variable with a numeric label? If that is so, why are
>>> you trying to compute an EDF? An EDF computes cumulative relative
>>> frequency of a random variable, which by definition is numeric. If we
>>> were talking about EDFs for a distribution of student course grades on
>>> a numeric point system by course, that would make some sense, but I
>>> don't see how the course IDs themselves qualify as being on an
>>> interval scale of measurement. Could you clarify your intent?
>>
>> Huh? gawesh asked for ecdf on numstrudents (not courseid)  ... pretty
>> clearly a numeric value for which an ECDF should make sense.
>>
>> --
>> David.
>>
>> --
>>>
>>> Dennis
>>>
>>> On Sun, Oct 16, 2011 at 8:31 AM, gj <[hidden email]> wrote:
>>>>
>>>> Hi,
>>>> Newbie here. I read the R for Beginners but i still don't get this.
>>>>
>>>> I have the following data (this is just an example) in a CSV file:
>>>>
>>>>   courseid numstudents
>>>>       101         209
>>>>       141          13
>>>>       246         140
>>>>       263           8
>>>>       321          10
>>>>       361          10
>>>>       364          28
>>>>       365          25
>>>>       366          23
>>>>       367          34
>>>>
>>>> I load my data using:
>>>>
>>>> fs<-read.csv(file="C:\\num_students_inallmodules.csv",header=T, sep=',')
>>>>
>>>> I want to get the ecdf. So, I looked at the ?ecdf which says
>>>> usage:ecdf(x)
>>>>
>>>> So I expected ecdf(fs$numstudents) to work
>>>>
>>>> Instead it just returned:
>>>> Call: ecdf(fs$numstudents)
>>>>  x[1:210] =      1,      2,      3,  ...,   3717,   4538
>>>>
>>>> After Googling, got this to work:
>>>> ecdf(fs$numstudents)(unique(fs$numstudents))
>>>>
>>>> But I don't understand why if the ?ecdf says usage is ecdf(x) ... I
>>>> need to use ecdf(fs$numstudents)(unique(fs$numstudents)) to get this
>>>> to work?
>>>>
>>>> Can somebody explain this to me?
>>>>
>>>> Regards
>>>> Gawesh
>>>>
>>>> ______________________________________________
>>>> [hidden email] mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>> PLEASE do read the posting guide
>>>> http://www.R-project.org/posting-guide.html
>>>> and provide commented, minimal, self-contained, reproducible code.
>>>>
>>>
>>> ______________________________________________
>>> [hidden email] mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>
>> David Winsemius, MD
>> Heritage Laboratories
>> West Hartford, CT
>>
>>
>

______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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Re: ecdf

gawesh
In reply to this post by Sarah Goslee
Hi Sarah,
Thanks for your very lucid explanations.
Thanks also to David and Dennis.

I got it completely. I now have some nice ggplot of a couple ecdf in
my paper :-)
Now on to do some matrix plots of correlation matrices and some lm().
I'm like a child in a candy shop. :-)

I'm learning something about R every day.

Regards
Gawesh

On Mon, Oct 17, 2011 at 2:11 AM, Sarah Goslee <[hidden email]> wrote:

> Hi,
>
> On Sun, Oct 16, 2011 at 8:48 PM, gj <[hidden email]> wrote:
>> David is right. I am looking for the ecfd for fs$numstudents. The
>> other column is just an id.
>>
>> I guess I don't know how to read the R documentation when it comes to functions.
>>
>> looking at the documentation, i now notice that it says "Compute an
>> empirical cumulative distribution function and not a vector.
>>
>> But still I would had assumed that in ecdf(x) ... the x is the argument.
>
> ecdf() is the function you're calling.
> x is your vector, for which you want the ECDF.
>
> num.ecdf <- ecdf(fs$numstudents)
>
> There. That's the ECDF.
>
> But the ECDF is a *function* - that's what the F stands for, after all.
>
> If you're looking for the percentiles for your data, you might try:
>
> num.ecdf(fs$numstudents)
>
> You might also try working the examples given in ?ecdf yourself, so
> that you can see exactly what's going on before you try it with your
> own data.
>
>
>> So ecdf(fs$numstudents)(unique(fs$numstudents))
>>     ===============  ==================
>>          function                       arguments
>>
>> Yes? But I can't read that from the documentation? I suspect it has
>> something to those dots .... in the arguments which I don't
>> understand.
>
> Yes.
>
> That's the condensed version of what I just proposed, done in
> one step, instead of two. The two-step version is definitely in
> the help. It doesn't have anything to do with the ..., which simply allow
> for other arguments to be passed.
>
>> Why it says usage ecdf(x) when it's clearly not the case?
>>
>> I don't get it.
>
> Clearly that is the case. ecdf(x) returns the empirical cumulative
> distribution *function* of the vector of data x.
>
> I'm not entirely sure what you think you should be getting. Perhaps
> if you explained your expectations, the list would be able to help
> you achieve them.
>
> Sarah
>
>> Gawesh
>>
>>
>> On Sun, Oct 16, 2011 at 11:02 PM, David Winsemius
>> <[hidden email]> wrote:
>>>
>>> On Oct 16, 2011, at 3:53 PM, Dennis Murphy wrote:
>>>
>>>> Hi:
>>>>
>>>> I don't understand what you're attempting to do. Wouldn't courseid be
>>>> a categorical variable with a numeric label? If that is so, why are
>>>> you trying to compute an EDF? An EDF computes cumulative relative
>>>> frequency of a random variable, which by definition is numeric. If we
>>>> were talking about EDFs for a distribution of student course grades on
>>>> a numeric point system by course, that would make some sense, but I
>>>> don't see how the course IDs themselves qualify as being on an
>>>> interval scale of measurement. Could you clarify your intent?
>>>
>>> Huh? gawesh asked for ecdf on numstrudents (not courseid)  ... pretty
>>> clearly a numeric value for which an ECDF should make sense.
>>>
>>> --
>>> David.
>>>
>>> --
>>>>
>>>> Dennis
>>>>
>>>> On Sun, Oct 16, 2011 at 8:31 AM, gj <[hidden email]> wrote:
>>>>>
>>>>> Hi,
>>>>> Newbie here. I read the R for Beginners but i still don't get this.
>>>>>
>>>>> I have the following data (this is just an example) in a CSV file:
>>>>>
>>>>>   courseid numstudents
>>>>>       101         209
>>>>>       141          13
>>>>>       246         140
>>>>>       263           8
>>>>>       321          10
>>>>>       361          10
>>>>>       364          28
>>>>>       365          25
>>>>>       366          23
>>>>>       367          34
>>>>>
>>>>> I load my data using:
>>>>>
>>>>> fs<-read.csv(file="C:\\num_students_inallmodules.csv",header=T, sep=',')
>>>>>
>>>>> I want to get the ecdf. So, I looked at the ?ecdf which says
>>>>> usage:ecdf(x)
>>>>>
>>>>> So I expected ecdf(fs$numstudents) to work
>>>>>
>>>>> Instead it just returned:
>>>>> Call: ecdf(fs$numstudents)
>>>>>  x[1:210] =      1,      2,      3,  ...,   3717,   4538
>>>>>
>>>>> After Googling, got this to work:
>>>>> ecdf(fs$numstudents)(unique(fs$numstudents))
>>>>>
>>>>> But I don't understand why if the ?ecdf says usage is ecdf(x) ... I
>>>>> need to use ecdf(fs$numstudents)(unique(fs$numstudents)) to get this
>>>>> to work?
>>>>>
>>>>> Can somebody explain this to me?
>>>>>
>>>>> Regards
>>>>> Gawesh
>>>>>
>>>>> ______________________________________________
>>>>> [hidden email] mailing list
>>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>>> PLEASE do read the posting guide
>>>>> http://www.R-project.org/posting-guide.html
>>>>> and provide commented, minimal, self-contained, reproducible code.
>>>>>
>>>>
>>>> ______________________________________________
>>>> [hidden email] mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>> PLEASE do read the posting guide
>>>> http://www.R-project.org/posting-guide.html
>>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>> David Winsemius, MD
>>> Heritage Laboratories
>>> West Hartford, CT
>>>
>>>
>>
>> ______________________________________________
>> [hidden email] mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>
>
> --
> Sarah Goslee
> http://www.stringpage.com
> http://www.sarahgoslee.com
> http://www.functionaldiversity.org
>

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