Chris,
I haven't seen anyone post a reply yet so thought I'd
throw in my thoughts. I'm no R expert!
When you talk about an exponential trend line are you
refering to:
1) y=ax^b
or
2) y=ae^(bx)
If 1) then take base10 logs of y and x and then fit them
with simple linear regression. Then calcula
As I said, I am new to R after spending far too many years using SAS. I'm
slowly getting the hang of R and like it very much.
Thanks for your insights and help.
Murray M Cooper, Ph.D.
Richland Statistics
9800 N 24th St
Richland, MI, USA 49083
Mail: richs...@earthlink.net
__
Dear All,
I am new to R and slowly learning how to use the system.
The following code is an exercise I was trying.
The intent is to generate 10 random samples of size 5 from
a vector with integers 1:10 and 2 missing values. I then want
to generate a matrix, for each sample which shows the freque
Paul,
I suggest looking up "observer agreement". The description of your study
sounds like a classical
categorical observer agreement problem. I can't give
a reference off the top of my head, but if you get
stuck, e-mail me and I'll try and find a ref to get you started.
Murray M Cooper, Ph.D.
You don't say what the error was, for the R factorial function,
but it is probably irrelevant for your question.
Factorials get to be big numbers rather quickly and unless you
are using a program that does arbitrary precission arithmetic
you will quickly exceed the precission limits, for storing
For science yes. For pleasure I'll still take a pint instead of 570ml!
Murray
- Original Message -
From: "Rolf Turner"
To: "Emmanuel Charpentier"
Cc:
Sent: Friday, April 03, 2009 6:18 PM
Subject: Re: [R] [OT ?] rant (was : Re: Conversions From standard to
metricunits)
On 4/04/2
The usual approach is to count the co-occurence within so many words of each
other.
Typical is between 5 words before and 5 words after a given word.
So for each word in the document, you look for the occurence of all other
words
within -5 -4 -3 -2 -1 0 1 2 3 4 5 words. Depending on the language
Just a word of caution. Having done a lot of work with 24 hour blood
pressure and ecg recordings, these series are seldom stationary which
presents problems with spectral analysis. I don't know what your ultimate
goal is, but in my work I found it often better to work with subsets, of the
serie
I'm deeply disappointed! I keep checking the mail list to see if you guys
are posting answers to questions I haven't asked yet. It would save me a lot
of time!
Best,
Murray
- Original Message -
From: "Rolf Turner"
To: "Sherri Heck"
Cc:
Sent: Wednesday, February 25, 2009 8:16 PM
S
samples.
Murray M Cooper, Ph.D.
Richland Statistics
9800 N 24th St
Richland, MI, USA 49083
Mail: richs...@earthlink.net
- Original Message -
From: "David Winsemius"
To: "Murray Cooper"
Cc: "Charlotta Rylander" ;
Sent: Friday, February 13, 2009 9:19 PM
Charlotta,
I'm not sure what you mean when you say simple linear
regression. From your description you have two groups
of people, for which you recorded contaminant concentration.
Thus, I would think you would do something like a t-test to
compare the mean concentration level. Where does the
regr
David,
If you really want to do a test on this data, I would suggest
a Fisher's Exact test, but you want to use hypergeometric
probabilities. You would probably want to try the CMH
test, if the function allows a single table and actually uses
hypergeometric probabilities.
My suggestion, would be
A recent thread on summary statistics, got me thinking. (Note this may not
happen often.) A function that would do summaries as describe below (similar
to SAS PROC UNIVARIATE) might be a nice addition to the main R system. Is
there a process by which functions, from packages can eventually be
inco
Nidhi,
You neglect to say what your OS is.
If you are using Windows, see the "R for Windows FAQ" faq 2.8. I haven't
looked, but I'm sure there is a similar item for other OS.
Murray M Cooper, Ph.D.
Richland Statistics
9800 N 24th St
Richland, MI, USA 49083
Mail: richs...@earthlink.net
-
I am new to R, so maybe I'm missing the point of your question. But why
wouldn't you just use sum(a,b)?
Murray M Cooper, Ph.D.
Richland Statistics
9800 N 24th St
Richland, MI, USA 49083
Mail: richs...@earthlink.net
- Original Message -
From: "Fuchs Ira"
To:
Sent: Thursday, February 0
Categorical data analysis is definitely the way you want to go.
Which test you use depends on how you are going to use the results.
For "quick and dirty" I would suggest using Fisher's exact test on all
2x2 submatricies of counts. In this case, with 4 treatments you have
6 possible 2x2 submatrici
Consider yourself lucky!
I'm sure there are many people who would
prefer not to see their name in the NYT. ;-)
Murray Coooper
- Original Message -
From: "Duncan Murdoch"
To: "Mark Difford"
Cc:
Sent: Thursday, February 05, 2009 10:16 AM
Subject: Re: [R] The Origins of R
On 2/5/200
David,
This may be a case of "If all you have is a hammer, everything looks like a
nail".
If all you want to do is remove the last line if it contains a CONTROL-Z,
why
not use something like perl to process the files?
Murray M Cooper, Ph.D.
Richland Statistics
9800 N 24th St
Richland, MI, USA
I was about to post a similar reply.
Stavros's reply was very eloquent and should be taken to heart!
Murray M Cooper, Ph.D.
Richland Statistics
9800 N 24th St
Richland, MI, USA 49083
Mail: richs...@earthlink.net
- Original Message -
From: "Stavros Macrakis"
To:
Sent: Sunday, February
I am working on a methodology for qualifying R, for GLP and GCP.
If I quailfy only the base R install, with no contributed packages, it
seems relatively simple to qualify R. However, from time to time I
will want to use a contributed package. If I use a contributed package,
does it leave anything
but been unable to locate the
file which contains model.matrix.
Thanks for your help.
Murray Cooper
- Original Message -
From: "Duncan Murdoch"
To: "zhijie zhang"
Cc:
Sent: Saturday, January 17, 2009 6:00 AM
Subject: Re: [R] Where to find the source codes for t
Do you really need the p-value or do you want to test at one
of the socially acceptable levels (i.e. .05 or .01). If all you want
is the test, use:
quantile(bootsample,c(0.025,0.975))
If the quantile range includes 0 then you decide there is no evidence
that the mean is different from zero, at t
Mostly I am interested in using R for statistics.
I am also interested in being able to look at source code.
I hope to be able to write extensions.
I tried the suggestion below but was unable to access vcov.lm.
methods(vcov)
[1] vcov.Arima* vcov.glm* vcov.lm*vcov.mlm* vcov.nls*
Non-v
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