Displaying 20 results from an estimated 7000 matches similar to: "median by geometric mean"
2011 Jan 17
1
median by geometric mean -- are we missing what's important?
Folks:
I know this may be overreaching, but are we missing what's important?
WHY do the zeros occur? Are they values less then a known or unknown
LOD? -- and/or is there positive mass on zero? In either case, using
logs to calculate a geometric mean may not make sense. Paraphrasing
Greg Snow, what is the scientific question? What is the model?
Cheers,
Bert
On Mon, Jan 17, 2011 at 9:13 AM,
2024 Jan 30
2
Use of geometric mean for geochemical concentrations
Dear Rich,
It depends how the data is generated.
Although I am not an expert in ecology, I can explain it based on a biomedical example.
Certain variables are generated geometrically (exponentially), e.g. MIC or Titer.
MIC = Minimum Inhibitory Concentration for bacterial resistance
Titer = dilution which still has an effect, e.g. serially diluting blood samples;
Obviously, diluting the
2024 Jan 22
2
Use of geometric mean .. in good data analysis
>>>>> Rich Shepard
>>>>> on Mon, 22 Jan 2024 07:45:31 -0800 (PST) writes:
> A statistical question, not specific to R. I'm asking for
> a pointer for a source of definitive descriptions of what
> types of data are best summarized by the arithmetic,
> geometric, and harmonic means.
In spite of off-topic:
I think it is a good
2005 Feb 19
2
Warnings by functions mean(), median()
Hello,
following functions doesnt work correct with my data: median(), geo.mean().
My datafiles contain more than 10.000 lines and six columns from a
flow-cytometer-measurment. I need the arithmetic and geometric mean and
median. For the calculation of the geometric mean i wrote following
function:
fix(geo.mean)
function(x)
{
n<-length(x)
2024 Jan 22
3
Use of geometric mean for geochemical concentrations
A statistical question, not specific to R.
I'm asking for a pointer for a source of definitive descriptions of what
types of data are best summarized by the arithmetic, geometric, and harmonic
means.
As an aquatic ecologist I see regulators apply the geometric mean to
geochemical concentrations rather than using the arithmetic mean. I want to
know whether the geometric mean of a set of
2014 Nov 13
1
metafor - code for analysing geometric means
?Dear All
I have some data expressed in geometric means and 95% confidence intervals. Can I code them in metafor as:
rma(m1i=geometric mean 1, m2i=geometric mean 2, sd1i=geometric mean 1 CI /3.92, sd2i=geometric mean 2 CI/3.92.......etc, measure="MD")
All of the studies use geometric means.
Thanks!
Edward
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2024 Jan 24
1
Use of geometric mean for geochemical concentrations [RESOLVED]
On Mon, 22 Jan 2024, Rich Shepard wrote:
> As an aquatic ecologist I see regulators apply the geometric mean to
> geochemical concentrations rather than using the arithmetic mean. I want to
> know whether the geometric mean of a set of chemical concentrations (e.g.,
> in mg/L) is an appropriate representation of the expected value. If not, I
> want to explain this to non-technical
2009 Aug 20
2
Geometric mean of rows in matrix
Is there a function or an easier way to computer geometric means of each
rows in a nxn matrix and spit out in an 1xn matrix ?
--
Edward Chen
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2009 Mar 18
2
geometric mean of probability density functions
Hi,
This is my first time posting to the mailing list, so if I'm doing something
wrong, just let me know. I've taken ~1000 samples from 8 biological
replicates, and I want to somehow combine the density functions of the
replicates. Currently, I can plot the density function for each biological
replicate, and I'd like to see how pool of replicates compares to a
simulation I conducted
1998 Nov 13
1
compute geometric mean
Hi:
I need to compute the geometric mean of a population. How i can do it??
thanks.
Jorge M. A. Magalhae
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2024 Jan 26
0
Use of geometric mean .. in good data analysis
Sorry to prolong a thread on something that is clearly off topic, but when Michael Meyer wrote
>by using the geometric mean all asymptotic results no longer apply.
that is flat our wrong. It's true that the geometric mean converges to something different that E[X], but it does indeed have an asymptotic distribution and one that makes sense in some contexts. There is no reason that
2005 Jan 04
1
quantiles for geometric distribution
Dear list,
I have got an array with observational values t and I would like to fit
a geometric distribution to it.
As I understand the geometric distribution, there is only one
parameter, the probability p. I estimated it by 1/mean(t).
Now I plotted the estimated density function by
plot(ecdf(t),do.points=FALSE,col.h="blue");
and I would like to add the geometric distribution. This
2024 Jan 22
1
Use of geometric mean for geochemical concentrations
better posted on r-sig-ecology? -- or maybe even stack exchange?
Cheers,
Bert
On Mon, Jan 22, 2024 at 7:45?AM Rich Shepard <rshepard at appl-ecosys.com>
wrote:
> A statistical question, not specific to R.
>
> I'm asking for a pointer for a source of definitive descriptions of what
> types of data are best summarized by the arithmetic, geometric, and
> harmonic
>
2010 Nov 10
2
Performing a geometric seqeunce using iterators?
I want to make a function for geometric seqeunce
since
testing=function(x){i=1;ans=1;while(true){ans=ans+(1/x)^i ; i=i+1}
;return(ans)}
doesn't work... the program is freeze... from my research, i know i should
use iterators.
I read iterators.pdf at
http://cran.r-project.org/web/packages/iterators/iterators.pdf and didnt
find it helps solving my problem at all...
Is there any sources I
2009 Apr 03
2
Geometric Brownian Motion Process with Jumps
Hi,
I have been using maxLik to do some MLE of Geometric Brownian Motion Process and everything has been going fine, but know I have tried to do it with jumps. I have create a vector of jumps and then added this into my log-likelihood equation, know I am getting a message:
NA in the initial gradient
My codes is hear
#
n<-length(combinedlr)
j<-c(1,2,3,4,5,6,7,8,9,10)
2006 Feb 26
1
Mouse hour glass and desktop
What does it mean when your mouse hour glass pointer turns into
a skull and cross bones symbol for a few seconds and is then
followed by your desktop icons being scrambled around to
different locations. This reminds me of a bug in the old
Windows 98 SE desktop.
What would cause this? This has happened to me once before
on Fedora 3 (I think, maybe 2).
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2023 Oct 17
2
Fwd: r-stats: Geometric Distribution
---------- Forwarded message ---------
From: Sahil Sharma <sahilsharmahimalaya at gmail.com>
Date: Tue, Oct 17, 2023 at 12:10?PM
Subject: r-stats: Geometric Distribution
To: <do-use-Contact-address at r-project.org>
Hey I want to raise one issue in *r-stats **geometric distribution *
function.
I have found the dgeom(x,p) which denotes probability density function of
geometric
2024 Jan 24
0
Use of geometric mean .. in good data analysis
By the Strong Law of Large Numbers applied to log(X) the geometric mean of X_1,...,X_n > 0 and IID like X converges toexp(E[log(X)]] which, by Jensen's inequality, is always? <= E[X] and is strictly less than E[X] except in trivial extreme cases.
In short: by using the geometric mean all asymptotic results no longer apply.
Michael Meyer
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2010 May 23
4
creating a reverse geometric sequence
Hello,
Can anyone think of a non-iterative way to generate a decreasing geometric
sequence in R?
For example, for a hypothetical function dg, I would like:
> dg(20)
[1] 20 10 5 2 1
where I am using integer division by 2 to get each subsequent value in the
sequence.
There is of course:
dg <- function(x) {
res <- integer()
while(x >= 1) {
res <- c(res, x)
x
2010 Aug 04
0
nls and geometric mean regression
Hello folks,
I'm seeking opinions about the validity of the following use of the
nls function...
A colleague and myself are working with tree allometric data
consisting of measurements of individual trees in semi-arid Australian
woodland species. We need to make predictions of trunk diameter (DBH:
diameter at breast height) given tree height and vice versa. I _think_
this falls into the