Displaying 20 results from an estimated 7000 matches similar to: "Dice simulation: Getting rep to re-evaluate sample()?"
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 =
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 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) *
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 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
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") >=
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 11
1
Using predict()?
I'm trying to solve a homework problem using R. The problem gives a list
of cricket chirps per second and corresponding temperature, and asks to
give the equation for the linear model and then predict the temperature
to produce 18 chirps per second. So far, I have:
> # Homework 11.2.1 and 11.3.3
> chirps <- scan()
1: 20
2: 16
3: 19.8
4: 18.4
5: 17.1
6: 15.5
7: 14.7
8: 17.1
9: 15.4
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 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 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
2006 Nov 21
1
NEWBIE: Help explaining use of lm()?
I'm attempting the heruclean task of teaching myself Introductory
Statistics and R at the same time. I'm working through Peter Dalgaard's
Introductory Statistics with R, but don't understand why the answer to
one of the exercises works. I'm hoping someone will have the patience to
explain the answer to me, both in the statistics and R areas.
Exercise 6.1 says:
The zelazo data
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
2007 Oct 16
1
Calculating confidence in an estimate including number of trials?
[Yes, this is related to a homework problem, but is not the problems
itself.]
In my mathematical statistics class, we've just learned about properties
of estimators, and I can now solve manually problems like this:
A sample of size n = 16 is drawn from a normal distribution where sigma
= 10 but mu is unknown. If mu = 20, what is the probability that the
estimator mu hat = Y bar will lie
2008 Jan 17
1
Any tools for working with US 2000 census data?
I've been given the job of extracting some data from the United States
2000 census (files at
http://www2.census.gov/census_2000/datasets/Summary_File_2/Maryland/all_
Maryland.zip 52M). I'm only interested in Census Block Groups (CBGs)
located within Baltimore City, Maryland. Additionally, I just have to
extract certain data fields. I think I'll be using Summary File 2. This
is my first
2010 Apr 24
4
DICE Coefficient of similarity measure
Hi,
I wanted the DICE coefficient (similarity measure for binary variables)
to be calculated in R and found that the "igraph" package has the option
of "similarity.dice" to do this. But, for this command, the input object
should be an igraph object. But, I have a dataframe of columns
containing 1's and 0's. Can I convert this dataframe into an igraph
object, so that
2011 Aug 30
3
Simulating distribution of max of two die
Hallo
I am teaching a very elementary intro course about R, and want to show
the students how to find the distribution of the maximum of rolling
two balanced die. Is there perhaps a more elegant way to do this,
other than the way I am using below? (I would like to show them two
ways - the one shown here, and perhaps and improved/elegant approach
(showing off the "beauty" of R.
2009 Feb 02
4
New to R
Hello All,
A colleague of mine started working with R and out of curiosity I did
some research on the language. Very nice. In my opinion this is one
of the best languages I've found for getting tasks I'm interested in
done. I wrote this simple die roller and was curious to know if it is
R enough.
##############################################################################
#
2007 Mar 06
3
Is there a quick way to count the number of times each element in a vector appears?
Hi there,
I'm writing a function that calculates the probability of different
outcomes of dice rolls (e.g., the sum of the highest three rolls of
five six-sided dice). I'm using the "combinations" function from the
"gtools" package, which is great: it gives me a matrix with all of the
possible combinations (with repetitions allowed). Now I want to count
the number