[R] question regarding basic stat question

[Peter Ehlers]

On 2011-02-22 08:10, Daniel Harris wrote:
> Thanks for the replies
>
> The file is below
>
> Height	Frequency
> 62	3
> 63	20
> 64	24
> 65	40
> 66	85
> 67	122
> 68	139
> 69	179
> 70	139
> 71	107
> 72	55
> 73	47
> 74	22
> 75	12
> 76	5
> 77	1
>
> I use the following
>
> data<- read.table("file",header=T)
> attach(data)
> summary(data)
>
> gives 2 summary fields height and frequency
>
> I want 1 based on height with frequency taken into account.
>
> If I do
>
> long<- as.data.frame(lapply(data, function(x) rep(x, Frequency)))
> long[,1]
> summary(long)
>
> The first column gives the answer that I am looking for but I just
> thought their maybe a better way without using the long variable

Sounds like you want the frequency-weighted summary statistics.
For the mean, look at ?weighted.mean.
For more comprehensive stats, check ?wtd.mean in the Hmisc pkg.
A search with pkg sos may provide more options.

Peter Ehlers
>
> Thanks
> Dan
>
> On Tue, Feb 22, 2011 at 1:32 PM, Bryan Hanson<hanson at depauw.edu>  wrote:
>> Daniel, how is the data stored?  The answer to your question may be as
>> simple as
>>
>>> df<- read.csv("filename.csv")
>>> summary(df)
>>
>> See ?read.csv for info on reading various file formats.
>>
>> HTH, Bryan
>> ****************
>> Prof. Bryan Hanson
>> Dept of Chemistry&  Biochemistry
>> DePauw University
>> 602 S. College Ave
>> Greencastle IN 46135 USA
>>
>> On Feb 22, 2011, at 7:20 AM, Daniel Harris wrote:
>>
>>> Hello
>>>
>>> Is it possible to get summary statistics (inc mean, sd etc) from a
>>> text file that has the following info stored in it?
>>>
>>> Height             Frequency
>>>
>>> 123                  5
>>> 124                  8
>>> 125                  3
>>> 126                  9
>>> 127                  7
>>>
>>> etc                   etc
>>>
>>> Now I know I can convert the file to a single list outside of R using
>>> python etc and I can convert the file to a single list inside R using
>>> a series of (what I find) complicated commands.
>>>
>>> Is there a simple way of doing summary(Height,Frequency)
>>>
>>> Thanks in advance
>>> Dan
>>>
>>> ______________________________________________
>>> 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.
>>
>>
>
> ______________________________________________
> 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.