Displaying 20 results from an estimated 2000 matches similar to: "Calculating confidence in an estimate including number of trials?"
2007 Oct 31
3
Homework help: Is this how CIs of normal distributions are computed?
I'm looking for a function in R similar to t.test() which was generously
pointed out to me yesterday, but which can be used for normally
distributed data.
To recap yesterday:
> x <- scan()
1: 62 52 68 23 34 45 27 42 83 56 40
12:
Read 11 items
> alpha<- .05
> t.test(x)
One Sample t-test
data: x
t = 8.8696, df = 10, p-value = 4.717e-06
alternative hypothesis: true
2007 Feb 08
4
NEWBIE: @BOOK help?
In Henric's recent post, he included this output:
@BOOK{R:Harrell:2001,
AUTHOR = {Frank E. Harrell},
TITLE = {Regression Modeling Strategies, with Applications to
Linear Models, Survival Analysis and Logistic
Regression},
PUBLISHER = {Springer},
YEAR = 2001,
NOTE = {ISBN 0-387-95232-2},
URL =
2006 Oct 19
1
Newbie: Selecting data
I've been working with R for all of about 8 hours, so anyone with more
experience than this should be able to help me. General comments about
my methods of work are also welcomed.
I have a table that I've imported thusly:
> w <- read.table("woodford.data", header=T)
> w
start therms gas KWHs elect temp days
1 10-Jun-98 9 16.84 613 63.80 75 40
2
2007 Dec 04
2
Learning to do randomized block design analysis
We just studied randomized block design analysis in my statistics class,
and I'm trying to learn how to do them in R. I'm trying to duplicate a
case study example from my textbook [1]:
> # Case Study 13.2.1, page 778
> cd <- c(8, 11, 9, 16, 24)
> dp <- c(2, 1, 12, 11, 19)
> lm <- c(-2, 0, 6, 2, 11)
> table <- data.frame(Block=LETTERS[1:5], "Score
2008 Mar 24
2
Newbie help with Sweave
I think I've gotten my Emacs/Sweave/R system set up correctly, thanks to
Vincent and Jim, but I haven't been successful getting my first document
produced. I'm trying to use one of Friedrich Leisch's examples,
http://www.ci.tuwien.ac.at/~leisch/Sweave/example-1.Snw. I cut and
pasted the text into a document sweaveexample.Rnw in Emacs. It seemed to
be processed successfully with R:
2007 Mar 01
2
Another newbie book recommandation question
I hope this question is sufficiently different from the other requests
for book recommendations that it's not repetitious. If not, I apologize
in advance.
I'm curious what standard reference books working statisticians, or
biostatisticians, have within easy reach of their desk. I'm a computer
systems administrator, and have a two-foot bookshelf directory under my
monitor that contains
2007 Aug 15
2
lmer coefficient distributions and p values
I am helping my wife do some statistical analysis. She is a biologist,
and she has performed some measurements on various genotypes of
mice. My background is in applied mathematics and engineering, and I
have a fairly good statistics background, but I am by no means a PhD
level expert in statistical methods.
We have used the lmer package to fit various models for the various
experiments that she
2006 Oct 17
4
Book recommendation for newbie to stats and R?
I'm trying to learn statistics and R at the same time. I have an
undergraduate science degree and one year of calculus (30 years ago),
but never took a stats course. I hope to take some stats courses in the
next year, but thought I would start to see how much I could teach
myself.
I work for an organization that analyses behavior change communication
programs regarding HIV/AIDS and
2023 Apr 13
3
Is LDAP + Kerberos without Active Directory no longer supported?
I have a server that runs stand-alone with an LDAP directory and a KDC .
The linux machines have sssd to allow unified users etc. The clients are
mostly MacOS and Windows machines that aren't part of an AD.
This config has worked for 15 years, but after upgrading Debian and
bringing in Samba Version 4.17.7-Debian it seems to be broken.
I believe this is related to:
2007 Oct 08
5
Dice simulation: Getting rep to re-evaluate sample()?
I'm trying to get R to simulate the sum of the values on 10 fair dice
(yes, it's related to a homework problem, but is not the problem
itself). I tried to do this:
> rep(sum(sample(1:6,100,replace=T)), times=10)
[1] 341 341 341 341 341 341 341 341 341 341
and noticed that sum(sample()) seems to be only evaluated once. How can
I overcome this, so that I get a vector of values that
2007 Oct 30
3
Homework help: Is this how CI using t dist are constructed?
I'm trying to replicate some of the examples from my textbook in R (my
text uses Minitab). In this problem, I'm trying to construct a 95%
confidence interval for these distance measurements [1]:
> # Case Study 7.4.1, p. 483
> x <- scan()
1: 62 52 68 23 34 45 27 42 83 56 40
12:
Read 11 items
> alpha<-.95
> mean(x) + qt(c((1-alpha)/2, 1-((1-alpha)/2)), df=length(x)-1) *
2008 Mar 20
2
Installation of R, Sweave, ESS and [X]Emacs on Windows?
I'm trying to get R, Sweave, ESS and XEmacs or emacs all installed and
working together on my Windows XP Pro system. I've got R 2.6.0 working
just fine, installed from the R Windows installer. I also have
CYGWIN_NT-5.1 with XEmacs 21.4 working okay. Can anyone point me to any
documentation on how to bring these together so that R code typed in
Xemacs can be run in R? I found the ESS
2007 Nov 07
1
Homework help: t test hypothesis testing with summarized data?
Is this how a t hypothesis test is done when I don't have the actual
data, but just the summarized statistics:
> #Homework 9.2.6 [1]
> n<-31
> xbar<-3.10
> s_x<-1.469
> m<-57
> ybar<-2.43
> s_y<-1.35
> s_pooled<- (((n-1)*s_x^2) + ((m-1)*s_y^2)) / (n + m - 2)
> s_pooled
[1] 1.939521
> t_obs <- (xbar - ybar) / (s_pooled * (sqrt(1/n + 1/m)))
2008 Jan 11
1
Oddities with RSiteSearch?
[If I knew who to report this to privately, I would. Sorry to embarrass
anyone who's just trying to contribute to the R-project.]
There seems to be some oddities with the RSiteSearch web page. When I
enter 'RSiteSearch("console")' I'm taken to
http://search.r-project.org/cgi-bin/namazu.cgi?query=console&max=20&resu
2007 Oct 16
2
Bootstrapping Contrasts for Repeated Measures ANOVA
I have executed a Repeated Measures ANOVA with one DV (latency) and
one within subject factor (acoustic condtion: 3 levels) by
bootstrapping my sampling distribution of F from the empirical sample
distribution. I chose to resample because the sample distribution
deviates from normality a lot.
The overall F is significant and now I wish to decompose this with
contrasts to ask if latencies to
2007 Aug 23
1
Clarification: Expedite scalar f(x) evaluation over vectors
Please note clarifications in <<>> below. My apologies for any confusion.
Thanks again,
Scott
---------- Forwarded message ----------
From: Scott Stark <stark.sc@gmail.com>
Date: Aug 23, 2007 1:03 PM
Subject: Expedite scalar f(x) evaluation over vectors
To: r-help@lists.r-project.org
Dear R community,
I am trying to code a fairly complex equation for optim(). My current
2007 Sep 07
2
Matlab's lsqnonlin
Hi! I'm translating some code from Matlab to R and I found a problem.
I need to translate Matlab's function 'lsqnonlin'
(http://www-ccs.ucsd.edu/matlab/toolbox/optim/lsqnonlin.html) into R,
and at the beginning I thought it would be the same as R's 'optim'. But
then I looked at the definition of 'lsqnonlin' and I don't quite see how
to make
2006 Oct 26
2
Newbie: Better way to do compound conditionals in subset?
There must be a better way to select the rows after 22-Apr-2004 and
before 01-Sep-2004 with a temperature below 65 than this:
> before2sw1 <- subset(energy.data, as.Date(start, format="%d-%b-%y") <
as.Date("01-Sep-04", format = "%d-%b-%y"))
> before2sw2 <- subset(before2sw1, as.Date(start, format="%d-%b-%y") >=
2007 Aug 29
3
OT: distribution of a pathological random variate
Folks,
I wonder if anything could be said about the distribution of a random variate x, where
x = N(0,1)/N(0,1)
Obviously x is pathological because it could be 0/0. If we exclude this point, so the set is {x/(0/0)}, does x have a well defined distribution? or does it exist a distribution that approximates x.
(The case could be generalized of course to N(mu1, sigma1)/N(mu2, sigma2) and one
2007 Aug 17
2
image plot with multiple x values
Hi,
New to R, I don't find a way to plot the following data with image():
x is a N * M matrix
y is a vector of length M
z is a N*M matrix
I wish to plot z as a greyscale image, but my x axis is different for
every row of the z data.
Here is a minimal example,
> theta<-c(3:6) # N
> y<-c(1:5) # M
>
> x<-theta%*%t(y)# N * M
> z<-sin(x) # N * M
>
> image(z)