Displaying 20 results from an estimated 10000 matches similar to: "Hypothsis simulation"
2010 Jan 19
1
(no subject)
I am considering testing:
Ho: Odds Ratio =1
H1: Odds Ratio <>1
How can I generate data from the null distribution for a specific
configuration of a Fisher exact test?
Jim
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2010 Sep 10
1
Simulation
I have two questions:
(1) How do you 'create' an 2 x 2 table in R using say an Odd ratio of 3 or
even 0.5
(2) If I have several 2 x 2 tables, how can I 'implement' dependence in the
tables with say 25 of the Tables having an odds ratio of 1 and 75 of the
tables having an odds ratio of 4?
Jim
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2005 Feb 28
2
A problem about outer()
Dear all,
I have something about function outer() that I can't understand. Just see the following example. The two NaNs are due to 0/0, but I can't figure out the cause of the last two errors. I wonder if some one can explain this for me.
___________________________________________________________________
> sx=rbinom(10,1,0.5);ot=rbinom(10,1,0.5);ag <- rbinom(10,100,0.3);ho <-
2009 Aug 26
2
Statistical question about logistic regression simulation
Hi R help list
I'm simulating logistic regression data with a specified odds ratio
(beta) and have a problem/unexpected behaviour that occurs.
The datasets includes a lognormal exposure and diseased and healthy
subjects.
Here is my loop:
ors <- vector()
for(i in 1:200){
# First, I create a vector with a lognormally distributed exposure:
n <- 10000 # number of study subjects
2009 Mar 21
5
Fisher test problem
Hi, I noted a discrepancy between R and openepi when I ran a fisher test
with the same matrix. In R:
> a=matrix(c(1,2,6,17), nrow=2)
> a
[,1] [,2]
[1,] 1 6
[2,] 2 17
> fisher.test(a, conf.int=T)
Fisher's Exact Test for Count Data
data: a
p-value = 1
alternative hypothesis: true odds ratio is not equal to 1
95 percent confidence interval:
0.02061498
2006 Jul 10
1
Query:chi-squre test
Hi,
I have calculated chi-square goodness of fit test,Sample coming from
Poisson distribution.
please copy this script in R & run the script
The R script is as follows
########################## start
#########################################
No_of_Frauds<-
c(4,1,6,9,9,10,2,4,8,2,3,0,1,2,3,1,3,4,5,4,4,4,9,5,4,3,11,8,12,3,10,0,7)
lambda<- mean(No_of_Frauds)
# Chi-Squared
2006 Jun 30
2
Query : Chi Square goodness of fit test
I want to calculate chi square test of goodness of fit to test,
Sample coming from Poisson distribution.
please copy this script in R & run the script
The R script is as follows
########################## start
#########################################
No_of_Frouds<-
c(4,1,6,9,9,10,2,4,8,2,3,0,1,2,3,1,3,4,5,4,4,4,9,5,4,3,11,8,12,3,10,0,7)
N <- length(No_of_Frouds)
# Estimation of
2011 Aug 27
1
Overdispersed GLM
Hi all,
I have the following data:
rep1_treat rep2_treat rep1_control rep2_control
2 3 4 5
100 20 98 54
0 1 2 3
23 32 27
2003 Oct 09
3
simulate binary data from a logistic regression model
Hi.
How can i simulate a binary data set from a logistic
regression model?I need to manipulate parameters and so
obtain my set of data.
I want to show the improve in analyzing binary data
with GLM(binomial) model instead of classical ANOVA or
NON-MODELS procedures(relative risk-odds ratio-Pearson
test of godness of fit...)
Can you say me what is the right function to use?
Do you know any
2010 Sep 23
2
Error: attempt to apply non-function
This code worked fine for me, then did some cleaning up of formatting using ESS (Emacs) and now I get this error, no idea what is causing it, all the brackets/parentheses seem to be balanced. What have I done wrong?
Thanks
Jim
p0.trial01 <- 0.25
TruOR01 <- 0.80
num.patients.01 <- 50
num.trials.01 <- 5
LOR01.het.in <- 0.00
num.sims <- 1
simLOR01 <-
2006 Sep 20
1
Simulation help
I'm trying to simulate trend data over a five year period. I want
different trend profiles...the simplest being a linear trend. I've been
using the following code:
patBdta1 <- NULL
for(i in 1:100)
patBdta1 <- rbind(patBdta1,c(yr1= mean(rbinom(50,1,.50)),
yr2 =mean(rbinom(50,1,.51)),
yr3 =mean(rbinom(50,1,.52)),
2006 Jun 16
0
The qurey about kolmogorov-smirnov test & adding the trendline to graph
I am hereby forwarding the data & method use to calculate the
Kolmogorov-Smirnov goodness of fit test made manually by me in R
launguage which deffers with the actual inbuilt formula as shown below.
Further I have plot the graph in R. In that graph how to add trendline
(i.e. straight line passing through maximum points in plot) to a Plot.
R script is as follows please run this script to see
2007 Nov 12
4
a repetition of simulation
Hello,
I have a simple (?) simulation problem.
I'm doing a simulation with logistic model and I want to reapet it 600
times.
The simulation looks like this:
z <- 0
x <- 0
y <- 0
aps <- 0
tiss <- 0
for (i in 1:500){
z[i] <- rbinom(1, 1, .6)
x[i] <- rbinom(1, 1, .95)
y[i] <- z[i]*x[i]
if (y[i]==1) aps[i] <- rnorm(1,mean=13.4, sd=7.09) else aps[i] <-
2010 Apr 13
1
Simulation problem.
Hi,
I have problem with simulating.
This is my task...
Suppose that there are N persons some of whom are sick with influenza. The
following assumptions are made:
* when a sick person meets a healthy one, the chance is á that the latter
will be infected
* all encounters are between two persons
Write a function which simulates this model for various values of
N (say, 10 000) and á (say, between
2009 Apr 17
5
Binomial simulation
Hi Guy's
I was wondering if someone could point me in the right direction.
dbinom(10,1,0.25)
I am using dbinom(10,1,0.25) to calculate the probabilty of 10 judges
choosing a certain brand x times.
I was wondering how I would go about simulating 1000 trials of each x value
?
regards
Brendan
--
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2011 Oct 14
1
Wilcoxon and the use of simulation
Dear forum users,
It's 3:35am and I am swamped with statistics homework lol
I'm terrible with R and this time I have no idea what the prof wants. Here
is the question:
Consider the (two-??sample) Wilcoxon rank statistic T = ?rank(Xi). For
n1=106 and n2=192, determine by simulation the ?=.05 critical point for
testing H0: ?=0, H1:?<0.
We can do this as follows:
For m=10000 (no wimpy
2006 Jul 16
17
AWDWR question
In an early section on Action View, showing code being put directly
into the rhtml file:
<% require ''date''
DAY_NAMES = %w{ Sunday Monday Tuesday Wednesday Thursday Friday Saturday }
today = Date.today %>
<h1>Hello, Dave</h1>
<p>
It''s <%= DAY_NAMES[today.wday] %>.
Tomorrow is <%= DAY_NAMES[(today + 1).wday %>.
</p>
I get this
2011 Apr 08
4
Fast version of Fisher's Exact Test
Is anyone aware of a fast way of doing fisher's exact test for a series of 2
x 2 tables in R? The fisher.test is really slow if n1=1000 and n2 = 1000.
--
Thanks,
Jim.
[[alternative HTML version deleted]]
2007 Nov 08
1
how to generate data in a simulation study
hello,
I have a problem in how to generate data in a simulation study.
I have a logistic model to evaluate p by 3 covariates.
I need to generate 4 variables: the binary outcome Y and 3 covariates:
gender (binary) and aps and tiss (continuous variables).
I have the logistic model which is the expected model:
log(p(y=1)/(1-p(y=1))=-1.659-0.05*sex+0.063*aps+0.04*tiss0)
I generate the outcome y like
2015 Jan 22
5
Simulación de modelo logit con interacción
Hola,
Deseo simular un modelo logit con interacción, estimar sus coeficientes y comprobar si son o no parecidos al modelo teórico. Con este ejemplo obtengo que los coeficientes estimados no se asemejan mucho a los originales. ¿Se le ocurre a alguien cuál es el motivo de esta discrepancia? ¿y cómo solucionarlo?
Muchas gracias
Emilio
logisticsimulation <- function(n){
dat <-