Displaying 20 results from an estimated 10000 matches similar to: "sample(c(0, 1)...) vs. rbinom"

2008 May 28

5

"rbinom" not using probability of success right

I am trying to simulate a series of ones and zeros (1 or 0) and I am using "rbinom" but realizing that the number of successes expected is not accurate. Any advice out there.
This is the example:
N<-500
status<-rbinom(N, 1, prob = 0.15)
count<-sum(status)
15 percent of 500 should be 75 but what I obtain from the "count" variable is 77 that gives the probability of

2012 Jan 03

1

nls and rbinom function: step factor 0.000488281 reduced below 'minFactor' of 0.000976562

I am trying to learn nls using a simple simulation. I assumed that the binomial prob varies linearly as 0.2 + 0.3*x in x {0,1},
and the objective is to recover the known parameters a=0.2, b=0.3
..data frame d has 1000 rows...
d$x<-runif(0,1)
d$y<-rbinom(1000,1,0.2+0.3*d$x)
table(d$y,cut(d$x,breaks=5));
(-0.000585,0.199] (0.199,0.399] (0.399,0.599] (0.599,0.799]

2015 Mar 24

4

Aleatoriedad

Hola de nuevo, ya empiezo a ser pesado ¿no? bueno, no importa porque
aprendemos todos. Eso, al menos, me parece.
Hoy estuve estudiando en R el tema de la aleatoriedad. Veo que hay
múltiples posibilidades pero me están chocando mucho. Encuentro que el
generador de números pseudo aleatorios es más pseudo de lo que debería.
Me explico, quiero generar 0 y 1 aleatorios. Estoy trabajando con una

2007 Jul 06

2

How does the r-distribution function work

I am trying to understand what rbinom function does.
Here is some sample code. Are both the invocations of bfunc effectively
doing the same or I am missing the point?
Thanks,
Pieter
bfunc <- function(n1,p1,sims) {
c<-rbinom(sims,n1,p1)
c
}
a=c()
b=c()
p1=.5
for (i in 1:10000){
a[i]=bfunc(30,p1,1)
}
b=bfunc(30,p1,10000)

2020 Oct 29

1

R: sim1000G

Hi,
I am using the sim1000G R package to simulate data for case/control study.
I can not figure out how to manipulate this code to be able to generate 10%
or 50% causal SNPs in R.
This is whole code provided as example on GitHub:
library(sim1000G)
vcf_file = "region-chr4-357-ANK2.vcf.gz" #nvariants = 442, ss=1000
vcf = readVCF( vcf_file, maxNumberOfVariants = 442 ,min_maf =

2011 Aug 26

2

How to find the accuracy of the predicted glm model with family = binomial (link = logit)

Hi All,
When modeling with glm and family = binomial (link = logit) and response values of 0 and 1, I get the predicted probabilities of assigning to my class one, then I would like to compare it with my vector y which does have the original labels. How should I change the probabilities into values of zero and 1 and then compare it with my vector y to find out about the accuracy of my

2012 Jan 30

1

mgcv bam() with grouped binomial data

Hello,
I'm trying to use the bam() function in the R mgcv package for a large set of grouped binary data. However, I have found that this function does not take data in the format of cbind(numerator, denominator) on the left hand side of the formula. As an example, consider the following
dat1 <- data.frame(id=rep(1:6, each=3), num=rbinom(18, size=10, prob=0.8), den=rbinom(18, size=5,

2007 Jan 19

1

naive bayes help

Hello
I have a rather simple code and for some reason it produces an error
message. If someone can tell me why and how to fix it, I would be very
greatful. Thank you in advance.
##### create data
set.seed(10)
n <- 200 # number of training points
n.test <- 200 # number of test points
p<-2 # dimension of input space
z <-

2010 May 10

1

Random walk

Hi everybody,
I am trying to generate two random walks with an specific correlation,
for example, two random walks of 200 time steps with a correlation 0.7.
I built the random walks with:
x<-cumsum(rnorm(200, mean=0,sd=1))
y<-cumsum(rnorm(200, mean=0,sd=1))
but I don't know how to fix the correlation between them.
With white noise is easy to fix the correlation using the function

2013 Jul 17

1

glmnet on Autopilot

Dear List,
I'm running simulations using the glmnet package. I need to use an
'automated' method for model selection at each iteration of the simulation.
The cv.glmnet function in the same package is handy for that purpose.
However, in my simulation I have p >> N, and in some cases the selected
model from cv.glmet is essentially shrinking all coefficients to zero. In
this case,

2012 Aug 27

3

How to generate a matrix of Beta or Binomial distribution

Hi folks,
I have a question about how to efficiently produce random numbers from Beta
and Binomial distributions.
For Beta distribution, suppose we have two shape vectors shape1 and shape2.
I hope to generate a 10000 x 2 matrix X whose i th rwo is a sample from
reta(2,shape1[i]mshape2[i]). Of course this can be done via loops:
for(i in 1:10000)
{
X[i,]=rbeta(2,shape1[i],shape2[i])
}
However,

2008 Sep 09

2

naive variance in GEE

Hi,
The standard error from logistic regression is slightly different
from the naive SE from GEE under independence working correlation structure.
Shouldn't they be identical? Anyone has insight about this?
Thanks,
Qiong
a<-rbinom(1000,1)
b<-rbinom(1000,2,0.1)
c<-rbinom(1000,10,0.5)
summary(gee(a~b, id=c,family="binomial",corstr="independence"))$coef

2013 May 21

2

problem with "transform" and "get" functions

Hello, I'm having a problem using the "transform" and "get" functions. I'm
probably making a dumb mistake, and I need help!
I start by making a small simulated dataset. I save the names of the
variables in "var.names." Without getting into the details of it, I have to
create a custom function to perform some statistics. As part of this, I
need to sequentially

2006 Apr 03

1

Does logistic regression require the independence of samples?

Dear list:
Thanks a lot for help. I have a question and I could not find clear answers
easily.
When we do logistic regression for one type of events of interest as a
proportion of a broader types of events, does the logistic regression assume
that the number of whole types of events should be independent with the
number of type of interest?
For example, if one type of events and the whole type

1997 Jul 09

1

R-beta: Problem with `rpois'

There is a problem with `rpois'. It does seem to take care about the
order of the arguments. This is an example:
> rpois(n=1,lambda=2)
[1] 3
> rpois(lambda=2,n=1)
[1] 2 0
It obviously uses the first argument as the number of samples to be
drawn, which is wrong.
I used Version 0.49 Beta (April 23, 1997).
Fredrik

1997 Jul 09

1

R-beta: Problem with `rpois'

There is a problem with `rpois'. It does seem to take care about the
order of the arguments. This is an example:
> rpois(n=1,lambda=2)
[1] 3
> rpois(lambda=2,n=1)
[1] 2 0
It obviously uses the first argument as the number of samples to be
drawn, which is wrong.
I used Version 0.49 Beta (April 23, 1997).
Fredrik

2011 May 04

1

hurdle, simulated power

Hi all--
We are planning an intervention study for adolescent alcohol use, and I
am planning to use simulations based on a hurdle model (using the
hurdle() function in package pscl) for sample size estimation.
The simulation code and power code are below -- note that at the moment
the "power" code is just returning the coefficients, as something isn't
working quite right.
The

2001 Apr 08

1

Random Number Testing...

Hi,
Suppose I want to test a set of random numbers (using the Binormal random
number generator), input the following command to generate a set of random
numbers:
test <- rbinom( 10000000, 1, 0.5 )
How can I, after obtaining the result, export the vector "test" into an text
file?
Then, suppose I want to do something like:
> x <- 1e10
> x
[1] 1e+10

2006 Aug 23

1

glm inside one self-defined function

Hi list,
I've searched in R-help and found some related discussions but still could
not understand this type of error. My own function is pretty complex, so I
would not put it here, but the basic algorithm is like this:
myfun<-function(k){
mydata<-...#by someway I create a data frame
mymodel<-glm(y~.,family=binomial(),data=mydata)
...#some other stuff
}
as I execute this

2006 Oct 09

1

testing for error

Dear R Helpers,
I want to test if a procedure within a loop has produced an error or not.
If the procedure has produced an error, then I want to ignore its result.
If it has not produced an error, then I want to use the result. The problem
In order to run the loop without crashing if the procedure produces an
error,
I place the routine inside a try() statement.
So, suppose I am trying to find