Displaying 20 results from an estimated 300 matches similar to: "ANOVA f-test"
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
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
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:
2010 Oct 20
1
Generate variable with Bivariate Normal Distribution
Dear All
I want to generate variable with Bivariate Normal Distribution by
use mean1 = a, variance1 = b, mean2 = c, variance2 = d, rho = e.
How I can do this.
Many Thanks.
IRD
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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
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
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
2018 Mar 25
3
Take average of previous weeks
Dear all,
I have weekly data by city (variable citycode). I would like to take the
average of the previous two, three, four weeks (without the current week)
of the variable called value.
This is what I have tried to compute the average of the two previous weeks;
df = df %>%
mutate(value.lag1 = lag(value, n = 1)) %>%
mutate(value .2.previous = rollapply(data = value.lag1,
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
2009 Aug 05
2
using ddply but preserving some of the outside data
I have a bit of a quandy. I'm working with a data set for which I
have sampled sites at a variety of dates. I want to use this data,
and get a running average of the sampled values for the current and
previous date.
I originally thought something like ddply would be ideal for this,
however, I cannot break up my data by date, and then apply a function
that requires information
1999 Mar 03
4
xfig device
Hi, I am VERY interested in getting the xfig driver so that I can edit
graphical output from R. Searching through the mail archives and reading
documentation isn't helping. Is there or isn't there a working driver for
this purpose. How can I get it? I tried looking at the development version
of the tarballs, but I didn't find anything that looked promising in there.
Also, does
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
2011 Mar 10
1
Help writing a Scheffe Contrast function for R
Hello,
As a new user of R (less than a month) I have got my hands on several books and am pouting through the net looking for help in gaining understanding of this powerful tool. I am becoming more proficient with using basic functions to conduct basic statistics. I am now looking to learn how to write code. After a few small worthless functions I decided to try to create a function that was
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
2010 Mar 20
2
EM algorithm in R
Please help me in writing the R code for this problem. I've been solving this
for 4 days. It was hard for me to solve it. It's a simulation problem in R.
The problem is
My true model is a normal mixture which is given as
0.5 N(-0.8,1) + 0.5 N(0.8,1). This model has two components.
I will get a random sample of size 100 from this model. I will do this 300
times.
That means, I will have
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
2006 Feb 15
2
aggregate data.frame using column-specific functions
Dear Colleagues,
does anybody know how to aggregate a data.frame using different functions for different columns?
Sincerely
___________________
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Consultant
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2010 Oct 08
1
Meta-analysis question
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