similar to: Normality test

Displaying 20 results from an estimated 30000 matches similar to: "Normality test"

2008 Jul 24
4
Is there an equivalent * operator?
Hi all, Is there an equivalent to the general * operator in R, where * can represent any character? I have a dataset, one column being date, date ranging between April-September, 97-06. I would like to be able to acquire the data for a specific month, say September, so that I can take average temperatures for the month, etc. I thought I would be able to do something like data.s1 <-
2008 Aug 21
4
Very confused with class
Hi all, I am very confused with class. I am looking at some weather data which I want to use as explanatory variables in an lm. R has treated these variables as factors (i.e. with different levels), whereas I want them treated as discretely measured continuous variables. So I need to reassign the class of these variables, right? Indeed, doing class(southwest$pressure) (pressure being air
2008 Sep 08
3
Saving functions
Hi, Appologies for the simple nature of this question, I am unable to find the answer in manuals (EG and introduciton to R). I have written a function in a text editor and saved it with an .R extension. It is saved in my working directory. How can I run it, do I need to use source? If so, how do I supply the arguments to the function? Or does it need to be saved in a particular directory?
2008 Aug 18
2
Using lag
Dear all, I am having difficulties using the seemingly-simple function lag. I have a dataframe with several weather variables (maxitemp, windspeed, rainfall etc), and the response variable (admissions). The dataset is fairly large (1530 observations). I simply want to model the response against a lag of a couple of the explanatory variables, say maxitemp and rainfall. I would like to look at
2008 Jul 22
4
Opening files from R terminal - appologies
Dear all, I appologise for cluttering up the list with such a basic question, however I have been unable to find the answer I want (possibly through my poor usage of the R help system). As I am visually impaired and using assistive technology, I think I would prefer to use R from the terminal mode, i.e. by running rterm.exe found in the bin directory. I have managed to set my working
2008 Jul 24
4
Just 2 more questions - for now!
Hi all, Thanks for the help with my previous post. I have just two more questions for the minute. I think I said in a previous post that I like to use the terminal, i.e. run rterm.exe. On exiting the terminal, I am asked if I want to save the workspace. If I hit y (yes), the workspace is just saved as .rdata in my working directory, does anyone know how I can name it directly from the
2008 Sep 05
1
Orthogonalization algorithms
Hi, I have eight vectors that I would like to orthogonalize preferably using R. The vectors are of considerable length, however due to their nature I know they satisfy the conditions needed to apply the Gram-Schmidt algorithm. Before I embark on some R coding, I wanted to check that there is no facility / function already around that computes the orthogonalized set of vectors? I have performed
2008 Sep 04
2
Coefficient of skewness
Hi, Is there a function in R to calculate the coefficient of skewness of some data? I had expected there to be one, but can find no information about it. Thanks for any pointers. Robin Williams Met Office summer intern - Health Forecasting robin.williams@metoffice.gov.uk [[alternative HTML version deleted]]
2008 Aug 28
1
Renaming objects
Hi, Is there any quick and easy way to rename a number of objects, without having to rename each one individually and then remove the old one? And if so, is there anything I can do to adjust the associated comments accordingly? Thanks for any help, Robin Williams Met Office summer intern - Health Forecasting robin.williams@metoffice.gov.uk [[alternative HTML version deleted]]
2008 Sep 09
2
How does predict.lm work?
Hi, Please could someone explain how this element of predict.lm works? From the help file ` newdata An optional data frame in which to look for variables with which to predict. If omitted, the fitted values are used. ' Does this dataframe (newdata) need to have the same variable names as was used in the original data frame used to fit the model? Or will R just look across consecutive
2008 Jul 21
1
Subsetting data by date
Hi all, Firstly I appologise if this question has been answered previously, however searching of the archives and the internet generally has not yielded any results. I am looking in to the effects of summer weather conditions (temperature, humidity etc), on the incidences of a breathing disorder brought on through smoking (COPD). I am fairly new to R and completely new to the idea of
2009 Oct 22
1
Normality test
I am having a hard time interpreting the results of the 'shapiro.test' for normality. If I do ?shapiro.test I see two examples using rnorm and runif. When I run the test using rnorm I get a wide variation of results. Most of this may be from variability of rnorm, samll sample size (limited to 5000 for the test), etc but if I repeat the test multiple times I can get: >
2008 Aug 28
1
Singularity?
Hi all, When using lm to model a response with 8 explanatory variables, one of the variables is not defined due to "singularities". I have checked the csv file from which the data come, there are no na's in the dataset, etc. What should I be looking for in this variable to correct the problem? Thanks for any help. Robin Williams Met Office summer intern - Health Forecasting
2009 May 04
2
normality test for large a large dataset ?
Hello, Do you know a R implemented normality test like the shapiro test but more suitable for large data set ? Thanks, _________________________________________________________________ Découvrez toutes les possibilités de communication avec vos proches [[alternative HTML version deleted]]
2008 Jul 12
5
shapiro wilk normality test
Hi everybody, somehow i dont get the shapiro wilk test for normality. i just can?t find what the H0 is . i tried : shapiro.test(rnorm(5000)) Shapiro-Wilk normality test data: rnorm(5000) W = 0.9997, p-value = 0.6205 If normality is the H0, the test says it?s probably not normal, doesn ?t it ? 5000 is the biggest n allowed by the test... are there any other test ? ( i know qqnorm
2008 Jan 29
1
Help needed on Normality test
Hi all T gurus, I would like to test if my dataset is indeed from N(0, 0.011908969). K.S. test gives following result: > ks.test(data, "pnorm", 0, 0.011908969) One-sample Kolmogorov-Smirnov test data: data D = 0.1092, p-value = 1.318e-05 alternative hypothesis: two-sided How ever "Shapiro-Wilk" test give following : >
2010 Jun 23
2
About normality tests...
Hi all, I have two very large samples of data (10000+ data points) and would like to perform normality tests on it. I know that p < .05 means that a data set is considered as not normal with any of the two tests. I am also aware that large samples tend to lead more likely to normal results (Andy Field, 2005). I have a few questions to ensure that I am using them right. 1) The Shapiro-Wilk
2008 Sep 03
2
R update
Hi all, please, someone can explain me how update my R version? thank you! giov -- View this message in context: http://www.nabble.com/R-update-tp19291451p19291451.html Sent from the R help mailing list archive at Nabble.com.
2008 Sep 04
1
saving an object
Hi there, I have a dataset stored in an object which has very huge volume of rows.I want to reuse it for comparing with other datasets.I dont want it to reload every time i run the script.Is there a way of saving a particular loaded object in the workspace and reusing it. Kindly help me. Ramya Thulasingam -- View this message in context:
2008 Sep 09
1
write dataframes
Hi, After manipulate my data I have ended up with 5 different data frames with different number of observations but the same number of variables (columns) An example, if I write str(object1), I see this, data.frame': 47 obs. of 3 variables: $ ORF : Factor w/ 245 levels "YAL038W","YAL054C",..: 10 19 38 39 44 45 50 51 59 60 ... $ mRNA : num 0.891 1.148 1.202