Displaying 20 results from an estimated 2000 matches similar to: "Student-t distributed random value generation within a confidence interval?"
2006 Sep 23
1
Fitdistr() versus nls()
Hello R-Users,
I'm new to R so I apologize in advance for any big mistake I might
be doing. I'm trying to fit a set of samples with some probabilistic
curve, and I have an important question to ask; in particular I have
some data, from which I calculate manually the CDF, and then I import
them into R and try to fit: I have the x values (my original samples)
and the y values
2004 Nov 24
2
confidence interval of a average...
I have a sample of lung capacities from a population measured against
height. I need to know the 95% CI of the lung capacity of a person of
average height.
I have fitted a regression line.
How do I get a minimum and maximum values of the 95% CI?
My thinking was that this has something to do with covariance, but how?
My other thinking was that I could derive the 0.975 (sqrt 0.95) CI for the
2011 Apr 09
1
loop and sapply problem, help need
Dear R experts
Sorry for this question
M1 <- 1:10
lcd1 <- c(11, 22, 33, 44, 11, 22, 33, 33, 22, 11)
lcd2 <- c(22, 11, 44, 11, 33, 11, 22, 22, 11, 22)
lcd3 <- c(12, 12, 34, 14, 13, 12, 23, 23, 12, 12)
#generating variables through sampling
pvec <- c("PR1", "PR2", "PR3", "PR4", "PR5", "PR6", "PR7",
2013 Jan 30
2
How does predict() calculate prediction intervals?
For a given linear regression, I wish to find the 2-tailed t-dist
probability that Y-hat <= newly observed values. I generate prediction
intervals in predict() for plotting, but when I calculate my t-dist
probabilities, they don't agree. I have researched the issues with variance
of individual predictions and been advised to use the variance formula
below (in the code).
I presume my
2015 Apr 10
2
Block Commit: [100 %]error: failed to pivot job for disk vda (Bug filed)
Hello List,
Seems like blockcopy --wait doesn't work work qemu-2.2.x.
I found someone else having the same problem, but it never went anywhere:
https://www.redhat.com/archives/libvirt-users/2015-January/msg00045.html
I went ahead and did some more debugging and created a bug report:
https://bugzilla.redhat.com/show_bug.cgi?id=1210903
I'm going to do some more debugging and hopefully
2007 Feb 05
3
Confidence intervals of quantiles
Can anyone please tell me if there is a function to calculate confidence
intervals for the results of the quantile function.
Some of my data is normally distributed but some is also a squewed
distribution or a capped normal distribution. Some of the data sets contain
about 700 values whereas others are smaller with about 100-150 values, so I
would like to see how the confidence intervals change
2011 Jan 28
5
Mean from confidence intervals
Dear List,
I am not sure if A) this is possible or B) the correct place to ask.
I am looking to find the mean - i have n, and the two-tailed confidence intervals 0.95 & 0.25 with a p-value of 0.05.
Can i find the mean from this data ?
Thanks
Peter
2012 Nov 15
1
how to create a 95 percent confidence interval using the diference of the mean using Bootstrap
Hello all, could you please tell me how to create a 95 percent confidence
interval using R, if I have the next data:
> blue
[1] 4 69 87 35 39 79 31 79 65 95 68 62 70 80 84 79 66 75 59 77 36 86 39
85 74
[26] 72 69 85 85 72
> red
[1] 62 80 82 83 0 81 28 69 48 90 63 77 0 55 83 85 54 72 58 68 88 83 78
30 58
[26] 45 78 64 87 65
Build a confidence interval of 95 % for the difference of the
2008 Jun 09
1
Student Distribution and Funtion qt
Hello,
I am trying to calculate and plot mean and confidence intervall for a set of data. This is the code that I am currently using:
means <- sapply(data, mean, na.rm=TRUE)
n <- sapply(data,length)
stdev <- sqrt(sapply(data, var, na.rm=TRUE))
ciw <- qt(0.98, n) * stdev / sqrt(n)
par(mgp=c(2,0.6,0), las=2, fin=c(7,3), mai=c(1,0.5,0.2,0.2), cex=0.8)
plotCI(x=means, uiw=ciw,
2008 Jan 03
2
confidence interval too small in nlme?
Hello,
I am interested in using nlme to model repeated measurements, but I don't seem
to get good CIs.
With the code below I tried to generate data sets according to the model given
by equations (1.4) and (1.5) on pages 7 and 8 of Pinheiro and Bates 2000 (having
chosen values for beta, sigma.b and sigma similar to those estimated in the
text).
For each data set I used lme() to fit a model,
2006 Apr 01
2
small sample size confidence interval by bootstrap
Hi, All:
I only have 4 samples. I wish to get a confidence interval around the mean.
Is it reasonable? If not, is there a way to compute a confidence interval
for such small sample size's mean?
Many thanks,
U
[[alternative HTML version deleted]]
2011 Jun 23
2
Confidence interval from resampling
Dear R gurus,
I have the following code, but I still not know how to estimate and extract
confidence intervals (95%CI) from resampling.
Thanks!
~Adriana
#data
penta<-c(770,729,640,486,450,410,400,340,306,283,278,260,253,242,240,229,201,198,190,186,180,170,168,151,150,148,147,125,117,110,107,104,85,83,80,74,70,66,54,46,45,43,40,38,10)
x<-log(penta+1)
plot(ecdf(x),
2012 Nov 06
1
Confidence intervals for Sen slope in zyp-package
Hi,
I have a question about the computation of confidence intervals in the zyp package, in particular using the functions zyp.sen and confint.zyp, or zyp.yuepilon.
(1) I'm a bit confused about the confidence intervals given by zyp.sen and confint.zyp. When I request a certain confidence interval in the function, the R output seems to deliver another confidence interval, e.g. when I set
2004 Jun 01
3
Confidence Bounds on QQ Plots?
What's the current best wisdom on how to construct confidence
bounds on something like a normal probability plot?
I recall having read a suggestion to Monte Carlo something like
201 simulated lines with the same number of points, then sort the order
statistics, and plot the 6th and 196th of these. [I use 201 not 200
because quantile(1:201, c(0.025, 0.975)) = 6 and 196 while
2008 Aug 20
3
Confidence Interval
Hi!
With the following script, I'm trying to make a demonstration of a
Confidence Interval, but I'm observing some differences on tails.
# Teste de média entre uma amostra e uma população normal
# Autor: Raphael de Freitas Saldanha
# Agosto de 2008
n <- 200 # Sample size
xbar <- 100 # Sample mean
s <- 2 # Sample SD
nc <- 0.95 # Confidence level (95%
2011 Nov 15
10
Adding a parameter to a custom Puppet type/provider
Hi All,
I''ve downloaded a Puppet module and I''m trying to add a parameter to it by
editing lib/puppet/type/<resource>.rb. I simply added:
newproperty(:pcfree) do
desc "My description here"
end
In the corresponding file in lib/puppet/provider, I do something with
:pcfree.
Whenever I call the resource from Puppet with my new parameter, it keeps
2003 Dec 12
1
Troubles joining a samba 3.0.1rc1 + LDAP domain
I am getting a bad username or password error when I try to logon to the
domain from a windows 2000 server. I can't find anything wrong with my
config and I'm using a root user that is in the directory with the uid
and gid set to 0.
The only thing I see in the logs is something about incorrect password
length, but I checked that my passwords are encrypted and I can access
shares as
2011 Jun 06
4
How do you handle deleted nodes with exported resources in this situation?
I have an issue where for a file type of an exported resource I must define
as such:
force => false,
replace => false,
Meaning the file is created, but do not replace after it''s added. I do this
because of the app modifies the config file after (I know bad idea on their
part).
How can I ensure this file is removed when I remove the node from
2013 Mar 15
0
confidence interval for survfit
The first thing you are missing is the documentation -- try ?survfit.object.
fit <- survfit(Surv(time,status)~1,data)
fit$std.err will contain the standard error of the cumulative hazard or -log(survival)
The standard error of the survival curve is approximately S(t) * std(hazard), by the delta
method. This is what is printed by the summary function, because it is what user's
2006 Mar 08
2
Problems using security=server for windows 2003 client.
I searched around but didn't find an answer to my question, hopefully
someone here knows how to fix this problem.
The issue is actually pretty simple, if I use "security = user" and add
a user with smbpasswd then I can connect to the share from windows 2003
server. However, if I set "security = server" then define the same
windows 2003 server as the password server then I