Displaying 20 results from an estimated 500 matches similar to: "Generate variable with Bivariate Normal Distribution"
2009 Dec 01
3
Using two (...) in a function
Hello R-Helpers,
I am not sure if it is a very simple question but I would like to use two
(...) in a function, for example,
this is a script where I would like to input the variable names (in one of
the (...)) and the variances associated to those variables which are not
calculated in the script because there is a specific software to calculate
it (the other (...))
data <- function
2011 Aug 16
4
a question about lm on t-test.
Hi all:
I have a question about lm on t-test.
data(sleep)
I wanna perform t-test to test the difference between the 2 groups:
I can use:
t.test(extra~group)
The t.test result shows that:t = -1.8608; mean1=0.75,mean2=2.33
But I still wanna use:
summary(lm(extra~group))
Intercept=0.75,which is mean1,just the same as t.test.
group2=1.58 means the difference of the 2 groups,so
2012 Mar 12
1
SEM eigen value error 0 X 0 matrix
Using R-studio, I am trying to run a structural equation model and I am
running into problems with testing my primary model. Once I specify
everything and try to run it I get this error:
Error in eigen(S, symmetric = TRUE, only.values = TRUE) : 0 x 0 matrix
And when I look at the object for my primary model in my workspace, which is
created after I specify it, it lists all my model components,
2010 Nov 23
1
Barplot and plot means with confidence intervals in the same plot
I want to obtain a barplot with error bars and a mean plot with error bars
with other scale on the left in the same plot. I need help to get the same
x axis (centered) when overlay two plots (barplot2 and plotCI (or
lineplot.CI) with errorbars), with diferent y axis. I use par (new=T) but
the X axis names are not centered with the figures.
An example of my data:
1999 Mar 07
1
ANOVA f-test
I have a rather basic question. How can I get R to generate a ANOVA table
and a f-value for a hypothesis test such as:
Data: group1 values: 5.2 4.5 6.0 6.1 6.7 5.8
group2 values: 6.5 8.0 6.1 7.5 5.9 5.6
...
H0: mean1 = mean2 = mean3 = mean4
HA: at least two means different
where I want to evaluate using a f test statistic?
F = MSTr/MSE
I'd like a table similar to one that
2003 Dec 04
6
get mean of several rows
Dear all!
After hours of trying around, I gave up:
I have a 2-dimensional array, and I know how to split it into its rows
and how to get the mean for every row using 'sapply'.
But what I want is to calculate the mean over the first n rows, and then
the second n rows, etc., so that I get a vector like:
v == mean1(row 1:5), mean2(row6:10),...
(trivial, you might say. I find it rather
2000 Aug 05
1
Problem reading in table with extra spaces
I wrote with C and created a file that I can read into S+, but R chokes
because I've got multiple spaces between some variables and there is a
space at the start of each data line. This happens becuase C was
right-justifying the numbers as it printed them out. It looks like
this:
T Run Seed IntAct Change f0 f0T0 f0T1 f0T2 average0 variance0
relentropy0 f1 f1T0 f1T1 f1T2 average1 variance1
2009 Jan 27
1
Problem with RMA using limma, oligo and pdInfoBuilder packages
Hi,
I am a Ph.D. student from Québec, Canada. I’m a beginner with R and
Bioconductor. Until now the only experience I have is in analyzing
microarray data using affy and limma packages. Now I am trying to analyze
Rat Gene 10 st arrays and I would like to run RMA analysis and Smyth
moderated t test on those arrays. Since no cdf official package is available
for those arrays, after reading many
2011 Sep 15
1
How to compute the power of a wilcoxon test?
Hello All,
I posted a similar question before, but the direction was driven to whether
my case is suitable for a wilcoxon test. After research about the
appropriateness, I am pretty sure that a wilcoxon test is the right tool for
my case. But how to compute the power of the test is still an unanswered
question bothering me.
The basic stats of my two paired samples are:
mean1 = 0.0032, sd1 =
2002 Mar 01
3
Power of t-test in R vs. S-PLUS
Dear all,
I found a discrepancy while performing a power calculation for a two sample
t-test in R and S-PLUS, respectively.
For given values of sample number (5 each), sd (0.2) , significance level
(0.01), and a desired power (80%) I looked for the difference in means.
These values differ: 0.5488882 in R and 0.4322771 in S-PLUS (see dump
below).
Did I overlook any detail or confuse some
2017 Aug 24
1
Problem in optimization of Gaussian Mixture model
Hello,
I am facing a problem with optimization in R from 2-3 weeks.
I have some Gaussian mixtures parameters and I want to find the maximum in
that
*Parameters are in the form *
mean1 mean2 mean3 sigma1 sigma2 sigma3 c1 c2 c3
506.8644 672.8448 829.902 61.02859 9.149168 74.84682 0.1241933
0.6329082 0.2428986
I have used optima and optimx to find the
2006 Mar 11
2
Draw level lines on the surface of a bivariate function
Hello,
Is it possible to draw level lines on the surface of a bivariate function?
In the following example, to draw surface and levels lines for a
multivariate normal law,
I use persp, trans3d, contourLines and lines,
but if the lines are correctly drawn, some parts of them are, of
course, visible
even if they are drawn on a non visible "face".
Any suggestion to avoid this problem
2010 Aug 18
2
functions and multiple levels
Hi,
I am trying to write a function;
I want to subtract the mean of each class in level 2 from the mean of each
class in level 1 and square the answer, eg.....
level.1 level.2 observation
1 1 0.5
1 1 0.2
1 2 0.6
1 2 0.4
2 3
2012 Dec 17
1
seeking a help on if function
Hello r helpers! Below is the whole coding for my programme. Before proceed more further, let me explain for you. First of all, I need to compute trimmed mean. Till that step is ok. Then I need to compute ssdw which is sum of square deviation. If I do equal trimming at both tail of distribution that I chose, I will use the first ssd formulae which is "a". But if I am doing unequal
2012 Apr 25
2
comparison of bivariate normal distributions
sorry for cross-posting
Dear all,
I have tow (several) bivariate distributions with a known mean and variance-covariance structure (hence a known density function) that I would like to compare in order to get an intersect that tells me something about "how different" these distributions are (as t-statistics for univariate distributions).
In order to visualize what I mean hear a little
2005 Jun 17
2
reading csv-data
Hi!
I have had this problem for a long time. I have tried to study the manuals and
search the mailing lists, but I can not solve this. I think there has to be one
simple solution to this, but I just can not find it.
I have saved the data in excel (csv-format). Then I read the data in R e.g.
>data <- read.csv2("example.csv", header=TRUE)
I look the data and it looks ok. E.g
2011 Aug 22
3
Multiple regression in R - unstandardised coefficients are a different sign to standardised coefficients, is this correct?
Hello,
I have a statistical problem that I am using R for, but I am not making
sense of the results. I am trying to use multiple regression to explore
which variables (weather conditions) have the greater effect on a local
atmospheric variable. The data is taken from a database that has 20391 data
points (Z1).
A simplified version of the data I'm looking at is given below, but I have
a
2008 Sep 22
1
lme problems
Hi,
I'm analysing a dataset in which the same 5 subjects (male.pair) were subjected to two treatments (treatment) and were measured for 12 successive days within each treatment (layingday). Overall 5*2*12=120 observations.
I want to test the effect of treatment, time (layingday) and their interaction. I have done so through the ANOVA below:
>
2009 Jun 22
3
Calculating "row standard deviations"
Hi R-helpers,
I have been struggling with calculating row and column statistics,
e.g. standard deviation.
I know that
> datac$Mean<-rowMeans(datac,na.rm=TRUE)
will give me row means.
I have tried to replicate those row means with the apply function:
> datac$Mean2<-apply(datac,2,mean)
so that I can replace the function argument with "sd" (instead of
mean) to get standard
2011 Aug 06
1
help with predict for cr model using rms package
Dear list,
I'm currently trying to use the rms package to get predicted ordinal
responses from a conditional ratio model. As you will see below, my
model seems to fit well to the data, however, I'm having trouble
getting predicted mean (or fitted) ordinal response values using the
predict function. I have a feeling I'm missing something simple,
however I haven't been able to