Help with function "fitdistr" in "MASS"

Hi, R users:

I want to fit my data into a normal distribution by using the command
"fitdistr" in "MASS".
I changed my data class from "ts" to "numeric" by
class(mydata)="numeric"
but after using "fitdistr", I got the result below
fitdistr(mydata,"normal")
mean    sd 
  NA     NA  
 (NA)   (NA) 

the help doc of "fitdistr" does not mention anything about that, thus I need
your help.

Thank you in advanced,
Saji from Shanghai
View this message in context: http://n4.nabble.com/Help-with-function-fitdistr-in-MASS-tp997609p997609.html
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I check my data again, and find that:
1. when the class of "mydata" is ts, I can't compute the sd of it. R returns
'NA'.
2. when I change the class from ts into numeric, R still can't compute the
sd of the data.

Any suggestion?
View this message in context: http://n4.nabble.com/Help-with-function-fitdistr-in-MASS-tp997609p997612.html
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And when I used the command below:
fitdistr(mydata, "normal", na.rm=TRUE)
the result is still the same.
View this message in context: http://n4.nabble.com/Help-with-function-fitdistr-in-MASS-tp997609p997615.html
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Please read the footer of this message.  ?fitdistr says

        x: A numeric vector.

and setting the class does not make it a numeric vector (it is just a 
label).  And fitdistr early on does

     if (missing(x) || length(x) == 0L || mode(x) != "numeric")
         stop("'x' must be a non-empty numeric vector")

so you do have a non-empty numeric vector.

It is likely that your data contains NAs, in which case the quoted 
result is correct.  But despite the posting guide we have no details 
of your 'mydata' and have to guess.

Hi, R users:

I want to fit my data into a normal distribution by using the command
"fitdistr" in "MASS".
I changed my data class from "ts" to "numeric" by

class(mydata)="numeric"
but after using "fitdistr", I got the result below

fitdistr(mydata,"normal")
 mean    sd
 NA     NA
(NA)   (NA)

the help doc of "fitdistr" does not mention anything about that, thus I need
your help.
The help page is not intended to be a very basic statistics/R textbook.
Thank you in advanced,
Saji from Shanghai
-- 
View this message in context: http://n4.nabble.com/Help-with-function-fitdistr-in-MASS-tp997609p997609.html
Sent from the R help mailing list archive at Nabble.com.

______________________________________________
R-help at r-project.org 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.

Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595
Hi, R users:

I want to fit my data into a normal distribution by using the command
"fitdistr" in "MASS".
I changed my data class from "ts" to "numeric" by

class(mydata)="numeric"
but after using "fitdistr", I got the result below

fitdistr(mydata,"normal")
  mean    sd 
  NA     NA  
 (NA)   (NA) 

the help doc of "fitdistr" does not mention anything about that, thus I need
your help.

Thank you in advanced,
Saji from Shanghai
Hi Sajj,

You hava NA in your data

try: fitdistr(na.exclude(mydata),"normal")
Bernardo Rangel Tura, M.D,MPH,Ph.D
National Institute of Cardiology
Brazil
Thank you,man. the problem solved.
Plus. when I got the parameters of the data.
And I used the "truehist(mydata)" to get a histogram of the data,
How can I draw a line of the distribution of the estimated parameters in the
histogram plot?

for example:
fitdistr(na.exclude(mydata),"normal")
mean         sd    
   4.052594   75.620350 
 ( 1.420743) ( 1.004617)
truehist(mydata)
After that, I got the histogram of mydata.
And I want plot a extra line of the density of a normal distribution of
mean=4.052594 and sd=75.620350 in the histogram plot?

thank you
On Sat, 2010-01-02 at 23:20 -0800, Saji Ren wrote:
Hi, R users:

I want to fit my data into a normal distribution by using the command
"fitdistr" in "MASS".
I changed my data class from "ts" to "numeric" by

class(mydata)="numeric"
but after using "fitdistr", I got the result below

fitdistr(mydata,"normal")
  mean    sd 
  NA     NA  
 (NA)   (NA) 

the help doc of "fitdistr" does not mention anything about that, thus I
need
your help.

Thank you in advanced,
Saji from Shanghai
Hi Sajj,

You hava NA in your data

try: fitdistr(na.exclude(mydata),"normal")

-- 
Bernardo Rangel Tura, M.D,MPH,Ph.D
National Institute of Cardiology
Brazil

______________________________________________
R-help at r-project.org 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.

View this message in context: http://n4.nabble.com/Help-with-function-fitdistr-in-MASS-tp997609p998258.html
Sent from the R help mailing list archive at Nabble.com.
Thank you,man. the problem solved.
Plus. when I got the parameters of the data.
And I used the "truehist(mydata)" to get a histogram of the data,
How can I draw a line of the distribution of the estimated parameters in the
histogram plot?

for example:
fitdistr(na.exclude(mydata),"normal")
     mean         sd    
   4.052594   75.620350 
 ( 1.420743) ( 1.004617)
truehist(mydata)
After that, I got the histogram of mydata.
And I want plot a extra line of the density of a normal distribution of
mean=4.052594 and sd=75.620350 in the histogram plot?
add this:

curve(dnorm(x, mean=4.052594, sd=75.620350), add=TRUE)

  -Peter Ehlers
thank you 

Bernardo Rangel tura wrote:
On Sat, 2010-01-02 at 23:20 -0800, Saji Ren wrote:
Hi, R users:

I want to fit my data into a normal distribution by using the command
"fitdistr" in "MASS".
I changed my data class from "ts" to "numeric" by

class(mydata)="numeric"
but after using "fitdistr", I got the result below

fitdistr(mydata,"normal")
  mean    sd 
  NA     NA  
 (NA)   (NA) 

the help doc of "fitdistr" does not mention anything about that, thus I
need
your help.

Thank you in advanced,
Saji from Shanghai
Hi Sajj,

You hava NA in your data

try: fitdistr(na.exclude(mydata),"normal")

-- 
Bernardo Rangel Tura, M.D,MPH,Ph.D
National Institute of Cardiology
Brazil

______________________________________________
R-help at r-project.org 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.

Peter Ehlers
University of Calgary
403.202.3921