Displaying 20 results from an estimated 4000 matches similar to: "Creating a specific skewed distribution"
2009 Oct 07
1
Simulate negative skewed, fat-tailed distribution
Hi guys
Is there a way in R to simulate/generate random numbers from a negative
skewed and fat
tailed distribution ? I would like to simulate a set of (discrete) data.
Regards,
Carlos
Carlos http://www.nabble.com/file/p25783889/graph.png graph.png
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2011 Nov 03
3
Plotting skewed normal distribution with a bar plot
Hi,
I need to create a plot (type = "h") and then overlay a skewed-normal
curve on this distribution, but I'm not finding a procedure to accomplish
this. I want to use the plot function here in order to control the bin
distributions.
I have explored the sn library and found the dsn function. dsn uses known
location, scaling and shape parameters associated with a given input
2011 Feb 23
1
Which glm "familiy" to choose with a skewed distribution of residuals, gaussian?
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2006 Mar 28
2
Skewed t distribution
Dear All,
I am working with skewed-t copula in my research recently, so I needed to
write an mle
procedure instead of using a standard fit one; I stick to the sn package. On
subsamples of the entire population that I deal with, everything is fine.
However, on the total sample (difference in cross-sectional
dimension: 30 vs 240) things go wrong - the objective function diverges to
infinity. I
2011 Mar 15
1
sample size of 2 groups of skewed data
Hi all:
I have a question on sample size calculation of 2 groups of data. If 2
groups of data are all normal distribution, then I can use the function
"n.indep.t.test.eq" from samplesize package.But if 2 groups of data are all
skewed distribution, but not normal distribution,how can I calculate the
sample size then?
I've tried many transformation (e.g. log arcsin…) in order to
2006 Aug 23
5
negatively skewed data; reflecting
Hi,
This problem may be very easy, but I can't think of how to do it. I have constructed histograms of various variables in my dataset. Some of them are negatively skewed, and hence need data transformations applied. I know that you first need to reflect the negatively skewed data and then apply another transformation such as log, square root etc to bring it towards normailty. How is it
2008 Aug 10
2
detect if data is normal or skewed (without a boxplot)
Hello all:
Is there a way to detect in R if a dataset is normally distributed or skewed without graphically seeing it? The reason I want to be able to do this is because I have developed and application with Visual Basic where Word,Access and Excel "talk" to each other and I want to integrate R to this application to estimate confidence intervals on fish sizes (mm). I basically want to
2011 Mar 21
1
Sample size of longitudinal and skewed data
Hi all:
I have a question about the sample size calculation.
It's a pilot study,which includes 2 groups(low,high),3 time point(3,6,9
monthes).Each person has 3 results which according to the
3 time points.So it's a longitudinal study.
I want to calculate the minimum sample size from the pilot study, but can't
find the solution since the data is highly skewed and
it's a
2010 Nov 30
1
researcher with highly skewed data set seeks help finding practical GLMM tutorial
Hi!
I am a psychologist who suspects that the only sensible way to analyse
a particular data set is to use generalised linear mixed models. I am
hoping that someone might be able to point me in the right direction
to find some very practical hands on documentation that might be able
to talk me through actually doing such an analysis?
So far in my searches the most useful document I have turned
2019 Mar 03
2
bug: sample( x, size, replace = TRUE, prob= skewed.probs) produces uniform sample
When `length( skewed.probs ) > 200' uniform samples are generated in R-devel.
R-3.5.1 behaves as expected.
`epsilon` can be a lot bigger than illustrated and still the uniform distribution is produced.
Chuck
> set.seed(123)
>
> epsilon <- 1e-10
>
> ## uniform to 200 then small
> p200 <- prop.table( rep( c(1, epsilon), c(200, 999-200)))
> ## uniform to 201
2004 Nov 11
2
Row labels are skewed in 'heatmap' (PR#7358)
Full_Name: Peter Fischer Hallin
Version: Version 1.8.1
OS: Irix64
Submission from: (NULL) (130.225.67.236)
I've made a script look like this:
exp <- read.table("graph/1933672048.cluster.data")
exp <- as.matrix(exp)
postscript("graph/1933672048.cluster.data.ps")
heatmap(exp,scale="none",cexCol=0.4,cexRow=0.2,col=custom,margins=c(5,5))
The row labels
2007 Jul 03
1
Plotting very skewed data in barplot
Dear R'ers,
I would like to use barplot or a similar function to plot data
demonstrating the distribution of the length of a kind of conservation in
about 25000 DNA sequences. My data look like this:
#Total sequences: 23873
0 19936
1 218
2 391
3 477
4 360
5 431
6 294
7 215
8 320
9 209
10 160
(.....)
99 0
100 1
101 0
102 0
103 1
104 0
105 0
106 0
107 0
108 0
109 1
Therefore, I would like
2013 Feb 13
2
e1071::skewness and psych::skew return NaN
Hello everyone,
Does anyone know what would cause the skewness() function (from
e1071), as well as skew() from psych, to return a value of NaN?
I have a vector of positively-skewed data
(https://docs.google.com/file/d/0B6-m45Jvl3ZmYzlHRVRHRURzbVk/edit?usp=sharing)
which these functions return a value for like normal:
> skewness( data ) # returns 1.400405
but when I instead give those
2006 May 11
1
Comparing skewness
Hello,
I'd appreciate any ideas on how to compare the skewness of two samples. In
my case, one sample is likely to be roughly normal and the other one
skewed. I could run two D'Agostino tests, but then I'll have to correct for
the family-wise error. What if both samples are skewed? If there are no
general tests (or they can't exist), I'd like to know.
Thanks,
Skirmantas
2005 Apr 03
3
'skewing' a normal random variable
Hi All;
The following question is directed more to statisticians on the list.
Suppose I have a normal random variable. Is there a transformation that I
can apply so that the new variable is slightly positively skewed.
I greatly appreciate your help.
Ashraf
2012 Feb 07
0
How to simulate rating scale from skewed and kurtosis ??
Hello all,
I need to simulate rating scale from skewed and kurtosis.
I would like to simulate a set of (discrete) data. ( n=1000, Item = 50 and
5 choice (1-5) )
Regards,
Vichr
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2010 Feb 08
0
confidence interval for negatively skewed, leptokurtic sample
Hello,
I?ve got a statistical problem that I hope you can help me with. It doesn?t
have to do directly with R, so if there?s another forum which would suit
better, please tell me!
Now here?s the problem:
I want to derive confidence intervals for a variable X, which is - given the
descriptive statistics - obviously negatively skewed and leptokurtic (i.e.
peaked). My aim is to make a statement
2008 Feb 29
0
Skewed RTP timestamps in SIP calls on Asterisk 1.4.18
Last week I migrated some of our servers to Asterisk 1.4.18 and we started
seeing audio drops of several seconds during SIP calls. After investigating
it we noticed that Asterisk was increasing the RTP timestamps abnormally
during a conversation.
I'm including a text file with a subset of the data collected by Wireshark
that shows the problem (I have the complete packet capture if anybody
2012 Feb 24
0
[newbie] how to represent very skewed spatial data?
What are good ways to (automatedly) plot (or othewise present) spatial data that is very skewed? E.g.
http://tinyurl.com/dn2VerySkewedSpatialData
produced with fields:image.plot. There are obviously outliers :-) which may or may not be "for real." At an exploratory stage in the investigation, I don't want to prejudge, I just want to show both
1 where the outliers are. This is not
2011 Aug 26
1
Comparing skewness of two distributions
I have two distributions. Both are left skewed. Is there a good
statistical approach to determining if the skew of distribution 1 is
statistically similar to the skew of distribution 2?
Thanks,
bp
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