Re: [R] normal distribution assumption for multi-level modelling

2012-04-19 Thread Cecile De Cat
Thanks.   I appreciate this isn't strictly an R question and will pursue on another list. The procedure I followed was inspired from @article{    Author = {Baayen, R. Harald and Milin, Petar},    Title = {Analysing Reaction Times},    Journal = {International Journal of Psychological Research},  

[R] normal distribution assumption for multi-level modelling

2012-04-18 Thread Cecile De Cat
Hello, I'm analysing reaction time data from a linguistic experiment (a variant of a lexical decision task). To ascertain that the data was normally distributed, I used *shapiro.test *for each participant (see commands below), but only one out of 21 returns a p value above p.0 05. f =

Re: [R] normal distribution assumption for multi-level modelling

2012-04-18 Thread Bert Gunter
Cecile: On Wed, Apr 18, 2012 at 8:21 AM, Cecile De Cat c.de...@leeds.ac.uk wrote: Hello, I'm analysing reaction time data from a linguistic experiment (a variant of a lexical decision task).   To ascertain that the data was normally distributed, I used *shapiro.test *for each participant

Re: [R] normal distribution assumption for multi-level modelling

2012-04-18 Thread Ben Bolker
Cecile De Cat c.decat at leeds.ac.uk writes: I'm analysing reaction time data from a linguistic experiment (a variant of a lexical decision task). To ascertain that the data was normally distributed, I used *shapiro.test *for each participant (see commands below), but only one out of 21

[R] normal distribution and floating point traps (?): unexpected behavior

2011-03-29 Thread Patrizio Frederic
dear all, here's a couple of questions that puzzled me in these last hours: # issue 1 qnorm(1-10e-100)!=qnorm(10e-100) qnorm(1-1e-10) == -qnorm(1e-10) # turns on to be FALSE. Ok I'm not a computer scientist but, # but I had a look at the R inferno so I write: all.equal(qnorm(1-1e-10) ,

Re: [R] normal distribution and floating point traps (?): unexpected behavior

2011-03-29 Thread Thomas Lumley
On Wed, Mar 30, 2011 at 10:33 AM, Patrizio Frederic frederic.patri...@gmail.com wrote: dear all, here's a couple of questions that puzzled me in these last hours: # issue 1 qnorm(1-10e-100)!=qnorm(10e-100) qnorm(1-1e-10) == -qnorm(1e-10) # turns on to be FALSE. Ok I'm not a computer

Re: [R] normal distribution and floating point traps (?): unexpected behavior

2011-03-29 Thread Duncan Murdoch
On 29/03/2011 5:33 PM, Patrizio Frederic wrote: dear all, here's a couple of questions that puzzled me in these last hours: # issue 1 qnorm(1-10e-100)!=qnorm(10e-100) qnorm(1-1e-10) == -qnorm(1e-10) # turns on to be FALSE. Ok I'm not a computer scientist but, # but I had a look at the R

Re: [R] Normal Distribution Quantiles

2011-01-09 Thread Michael Bedward
Just to add to the silly solutions, here's how I would have done it... mu - 40 sdev - 10 days - 100:120 # range to explore p - 0.8 days[ match(TRUE, qnorm(0.2, mu*days, sqrt(sdev * sdev * days)) = 4000) ] Michael On 9 January 2011 08:48, Bert Gunter gunter.ber...@gene.com wrote: If I

Re: [R] Normal Distribution Quantiles

2011-01-09 Thread Rainer Schuermann
Altogether I got five more or less silly solutions (not my judgment!), some of them further discussed in private mail, for a problem where my expectation was to get a simple one-liner back: Check ?clt or so... Fortunately, with all of them I seem to arrive at a result that is consistent with

[R] Normal Distribution Quantiles

2011-01-08 Thread Rainer Schuermann
This is probably embarrassingly basic, but I have spent quite a few hours in Google and RSeek without getting a clue - probably I'm asking the wrong questions... There is this guy who has decided to walk through Australia, a total distance of 4000 km. His daily portion (mean) is 40km with an

Re: [R] Normal Distribution Quantiles

2011-01-08 Thread David Winsemius
On Jan 8, 2011, at 6:56 AM, Rainer Schuermann wrote: This is probably embarrassingly basic, but I have spent quite a few hours in Google and RSeek without getting a clue - probably I'm asking the wrong questions... There is this guy who has decided to walk through Australia, a total

Re: [R] Normal Distribution Quantiles

2011-01-08 Thread Rainer Schuermann
Sounds like homework, which is not an encouraged use of the Rhelp list. You can either do it in theory... It is _from_ a homework but I have the solution already (explicitly got that done first!) - this was the pasted Latex code (apologies for that, but in plain text it looks unreadable[1],

Re: [R] Normal Distribution Quantiles

2011-01-08 Thread David Winsemius
On Jan 8, 2011, at 9:25 AM, Rainer Schuermann wrote: Sounds like homework, which is not an encouraged use of the Rhelp list. You can either do it in theory... It is _from_ a homework but I have the solution already (explicitly got that done first!) - this was the pasted Latex code

Re: [R] Normal Distribution Quantiles

2011-01-08 Thread Charles C. Berry
On Sat, 8 Jan 2011, Rainer Schuermann wrote: Sounds like homework, which is not an encouraged use of the Rhelp list. You can either do it in theory... It is _from_ a homework but I have the solution already (explicitly got that done first!) - this was the pasted Latex code (apologies for

Re: [R] Normal Distribution Quantiles

2011-01-08 Thread Joshua Wiley
On Sat, Jan 8, 2011 at 6:25 AM, Rainer Schuermann rainer.schuerm...@gmx.net wrote: It is _from_ a homework but I have the solution already (explicitly got that done first!) - this was the pasted Latex code (apologies for that, but in plain text it looks unreadable[1], and I thought everybody

Re: [R] Normal Distribution Quantiles

2011-01-08 Thread Bert Gunter
If I understand what you have said below, it looks like you do NOT have the problem solved manually. You CAN use qnorm , and when you do so, your equation yields a simple quadratic which, of course, has an exact solution that you can calculate in R. Of course, one can use uniroot or whatever to

Re: [R] Normal distribution (Lillie.test())

2010-02-26 Thread Bosken
Hi Greg, I'm making NoiseGenerators with different noise sources and components, the meaning of my tests with R is to know which NoiseGenerator approached most the Normal distribution function... Thanks, for all the reactions. Bosken Greg Snow-2 wrote: Do your NoiseGenerotors need to

Re: [R] Normal distribution (Lillie.test())

2010-02-25 Thread Greg Snow
...@r-project.org [mailto:r-help-boun...@r- project.org] On Behalf Of Bosken Sent: Tuesday, February 23, 2010 4:13 AM To: r-help@r-project.org Subject: Re: [R] Normal distribution (Lillie.test()) Hi, Thanks for your reaction; How do you come to the decision that my data not is normal

Re: [R] Normal distribution (Lillie.test())

2010-02-25 Thread Greg Snow
Data Center Intermountain Healthcare greg.s...@imail.org 801.408.8111 -Original Message- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- project.org] On Behalf Of Bosken Sent: Thursday, February 25, 2010 10:21 AM To: r-help@r-project.org Subject: Re: [R] Normal

Re: [R] Normal distribution (Lillie.test())

2010-02-25 Thread Ravi Varadhan
-Original Message- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Bert Gunter Sent: Thursday, February 25, 2010 12:24 PM To: 'Greg Snow'; 'Bosken'; r-help@r-project.org Subject: Re: [R] Normal distribution (Lillie.test()) ... But,quoting Pogo, We have met

Re: [R] Normal distribution (Lillie.test())

2010-02-25 Thread Bosken
Hi, Thanks for your reaction. The purpose of my test is to check if my NoiseGenerators really are Normal Distributed en witch circuit is the best! So I need some good test to do this. But what with: Fortune(117) and fortune(234), can't find anything about it.. Thanks for the help! Bosken --

Re: [R] Normal distribution (Lillie.test())

2010-02-25 Thread David Winsemius
On Feb 25, 2010, at 12:20 PM, Bosken wrote: Hi, Thanks for your reaction. The purpose of my test is to check if my NoiseGenerators really are Normal Distributed en witch circuit is the best! So I need some good test to do this. But what with: Fortune(), can't find anything about it..

Re: [R] Normal distribution (Lillie.test())

2010-02-23 Thread Bosken
Hi, Thanks for your reaction; How do you come to the decision that my data not is normal distributed? With the 69-95-99.7 test and Q-Q plot seems it ok! But these test are not exact, they only give you an image. Gr. Bosken -- View this message in context:

[R] Normal distribution (Lillie.test())

2010-02-22 Thread Bosken
Hi all, I have a dataset of 2000 numbers ( it's noise measured with a scoop ) Now i want to know of my data is normal distributed (Gaussian distribution). I did already: - 68-95-99.7 test - Q-Q-plot and now i used nortest library and the Lilli.test() However i don't understad the output?

Re: [R] Normal distribution test

2009-11-18 Thread Markus Mehrwald
Thank you for all the answers! Kjetil, I am not sure if we are talking about the same thing. I only have a two dimensional normal distribution which leads to three dimensional data. You mean with reject I should not do such a test? My data files contain about 26 points which I can reduce

Re: [R] Normal distribution test

2009-11-17 Thread Johannes Graumann
Markus Mehrwald wrote: Hi all, I am completely new to R and my knowledge of statistics is quite small so I hope you can help my. I have three dimensional point data which represents (and this is what I do not know for sure) a normal distribution. Now I want to test if this is true or not

Re: [R] Normal distribution test

2009-11-17 Thread Kjetil Halvorsen
On Tue, Nov 17, 2009 at 11:17 AM, Markus Mehrwald mehrw...@ira.uka.de wrote: Hi all, I am completely new to R and my knowledge of statistics is quite small so I hope you can help my. I have three dimensional point data which represents (and this is what I do not know for sure) a normal

Re: [R] Normal distribution test

2009-11-17 Thread rkevinburton
This is probably an even more basic question but shapiro.test return both the statistic (w) and the significance (pw) of the statistic. For this test the null-hypothesis is that the distirbution is not normal so very small values of pw would mean that there is very little chance that the

Re: [R] Normal distribution test

2009-11-17 Thread Duncan Murdoch
On 11/17/2009 10:07 AM, rkevinbur...@charter.net wrote: This is probably an even more basic question but shapiro.test return both the statistic (w) and the significance (pw) of the statistic. For this test the null-hypothesis is that the distirbution is not normal so very small values of pw

Re: [R] Normal distribution

2009-11-08 Thread mandalic05
Normal distribution check within R can be done with functions available in nortest package. This package consists of several normality tests. In order to install package type install.packages('nortest'). Afterwards, you should consider running ks.test() only if mu and sigma parameters are known

Re: [R] Normal distribution

2009-10-02 Thread Colin Millar
Sent: Thursday, October 01, 2009 12:47 PM To: r-help@r-project.org Subject: [R] Normal distribution Hi, I am dealing with how to check in R if some data that I have belongs to a normal distribution or not. I am not interested in obtaining the theoreticall frequencies. I am only interested

Re: [R] Normal distribution

2009-10-02 Thread Greg Snow
, 2009 10:47 AM To: r-help@r-project.org Subject: [R] Normal distribution Hi, I am dealing with how to check in R if some data that I have belongs to a normal distribution or not. I am not interested in obtaining the theoreticall frequencies. I am only interested in determing if (by means

[R] Normal distribution

2009-10-01 Thread Noela Sánchez
Hi, I am dealing with how to check in R if some data that I have belongs to a normal distribution or not. I am not interested in obtaining the theoreticall frequencies. I am only interested in determing if (by means of a test as Kolmogorov, or whatever), if my data are normal or not. But I have

Re: [R] Normal distribution

2009-10-01 Thread Richardson, Patrick
?shapiro.test -Original Message- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Noela Sánchez Sent: Thursday, October 01, 2009 12:47 PM To: r-help@r-project.org Subject: [R] Normal distribution Hi, I am dealing with how to check in R if some data

Re: [R] Normal distribution

2009-10-01 Thread Steve Lianoglou
: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Noela Sánchez Sent: Thursday, October 01, 2009 12:47 PM To: r-help@r-project.org Subject: [R] Normal distribution Hi, I am dealing with how to check in R if some data that I have belongs to a normal

Re: [R] Normal distribution

2009-10-01 Thread Richardson, Patrick
: Thursday, October 01, 2009 1:18 PM To: Richardson, Patrick Cc: Noela Sánchez; r-help@r-project.org Subject: Re: [R] Normal distribution Hi, I think you can also use a qq-plot to do the same, no? You won't get a statistic score + p.value, but perhaps you're more of a visual person? :-) -steve On Thu

Re: [R] Normal distribution

2009-10-01 Thread Peter Ehlers
Noela, Package nortest has 5 tests of normality. A word of caution: the wording of your question suggests that you believe that, if the test you use does not reject the normality hypothesis, you then have proof that your data come from a Normal distribution. That's *NOT* true. Normality will

Re: [R] Normal distribution

2009-10-01 Thread Peter Ehlers
:56 PM, Richardson, Patrick patrick.richard...@vai.org wrote: ?shapiro.test -Original Message- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Noela Sánchez Sent: Thursday, October 01, 2009 12:47 PM To: r-help@r-project.org Subject: [R] Normal

Re: [R] Normal distribution

2009-09-12 Thread KABELI MEFANE
 Dear All   let me go one step further by asking you if you could help me show that the distribution of this data in normal.  have a little idea (by trial and error) but i seem to not fully understand how its done.   H-rnorm(100, mean=5, sd=3000) par(las=1) hist(H, breaks=seq(4, 6,

Re: [R] Normal distribution

2009-09-12 Thread jim holtman
Why don't you just do this: H-rnorm(100, mean=5, sd=3000) par(las=1) hist(H, breaks=seq(4, 6, 1000), freq=F) f- function(x) exp(-(x-5000)^2/1800)/sqrt(1800*pi) x- seq(4, 6, 100) lines(x, dnorm(x, 5, 3000)) On Sat, Sep 12, 2009 at 5:47 PM, KABELI

Re: [R] Normal distribution

2009-09-12 Thread KABELI MEFANE
Thank You   It really works fine and i do understand it. Now i can sleep, its 0200 hours here. Why don't you just do this: H-rnorm(100, mean=5, sd=3000) par(las=1) hist(H, breaks=seq(4, 6, 1000), freq=F) f- function(x) exp(-(x-5000)^2/1800)/sqrt(1800*pi) x- seq(4,

Re: [R] Normal distribution with R

2009-05-01 Thread Eik Vettorazzi
Hi James, (qnorm(.9)-qnorm(.1)) is the width of the 80% CI of a standard normal distribution. So its a kind of standardization the other way round calculating sd from this. The same holds for arbitrary p1 and p2. Without loss of generality (since the normal distribution is symmetric), assume

[R] Normal distribution with R

2009-04-29 Thread guox
If we knew two pth quantiles for a normal distribution, is it possible that we can find mean and sigma for the normal distribution using R? Let x ~ norm(mean, sigma). Suppose that qnorm(0.9,mean,sigma) and qnorm(0.1,mean,sigma) are known. Can we find mean and sigma using R? Thanks, -james

Re: [R] Normal distribution with R

2009-04-29 Thread Eik Vettorazzi
Hi James its just simple calculus, since with q90-qnorm(.9,me,sd) q10-qnorm(.1,me,sd) mean-(q90+q10)/2# the normal distribution is symmetric around the mean sd-(q90-q10)/ (qnorm(.9)-qnorm(.1)) # between 10th and 90th are qnorm(.9)-qnorm(.1)=2.563103sds hth. g...@ucalgary.ca schrieb: If