search for: linear

Hi, I have a question to ask. if in a linear regression model, the independent variables are not statistically significant, is it necessary to test these variables in a non-linear model? Since most of non-linear form of a variable can be represented to a linear combination using Taylor's theorem, so I wonder whether the non-linear form is...

Please advice on the package I should use to run a linear regression model (weighted least squared) with linear equality constraint. I initially tried "constrOptim" but it turned out that it only supported inequality linear constraint. Thank you very much in advance. Cheers, Jon -- View this message in context: http://r.789695.n4.nabble.com...

Hello, I am looking for a measure of linearity in the relationship between two variables. Specifically, I have two variables for which the relationship is reasonably linear over a certain range of values, and then diverges from linearity at either end of the range, as one or other variable "saturates" at a maximum or minimum value...

...ics, so I hope you will excuse what may seem like a very basic question. I'm trying to use R to do an ANOVA analysis for some data with an unbalanced design, and while I was trying to figure that out, I got confused about the purpose of the "lm". All definitions I can find of "linear model" are of the form: y = a + b * x + e In other words, y is only linear in the dependent variable(s) x. However, the lm model seems to support higher order polynomials, e.g.: > lm(dist ~ speed + I(speed^2)+I(speed^3), cars) Is there some sense in which that model is "linear...

Dear friends, I searched the R site and found a lot of results on general linear model and generalized linear model , and i was confused by them. Here, I only want to get some concise answers on the following questions and i'll study it by your hints: 1. Which function(package) could be used to fit the general linear model ? 2. Which function(package) could be used to fit...

Dear List, how can I obtain the value of r suqared for a non-linear model? For linear models it can be found in the summary() of the model but for non-linear models I just don't know. Please help! Anna

Hello. I am still a newbie in R. Excuse me if I am asking something obvious. My efforts to get an answer through browsing the mailing archives failed. I want to perform an augmented Dickey-Fuller test and to obtain AIC and BIC and to be able to impose some linear restrictions on the ADF regression so as to decide the correct order of autoregression. However I could find no obvious way to impose linear restrictions or to obtain AIC from the the result of ADF.test from uroot. That is why I turned to systemfit. I ran the ADF regression with systemfit and obtai...

I am trying to understand what is the difference between linear and polynomial kernel: linear: u'*v polynomial: (gamma*u'*v + coef0)^degree It would seem that polynomial kernel with gamma = 1; coef0 = 0 and degree = 1 should be identical to linear kernel, however it gives me significantly different results for very simple data...

..."********** Using VGAM function gamma2 **********")) + modl2<- vglm(MidPoint~Count,gamma2,data=modl.subset,trace=TRUE,crit="c") + print(coef(modl2,matrix=TRUE)) + print(summary(modl2)) [1] "********** Using VGAM function gamma2 **********" VGLM linear loop 1 : coefficients = 0.408464609241, 3.255887520104, -0.000220585671 VGLM linear loop 2 : coefficients = 2.34723239e-01, 1.28969691e+00, -4.52393778e-05 VGLM linear loop 3 : coefficients = 2.19500481e-01, 1.92534895e+00, -3.02160949e-05 VGLM linear loop 4 : coefficients...

Hi everyone, i?m a new user of R and i?m trying to translate an linear optimization problem from Matlab into r. The matlab code is as follow: options = optimset('Diagnostics','on'); [x fval exitflag] = linprog(f,A,b,Aeq,beq,lb,ub,[],options); exitflag fval x=round(x); Where: f = Linear objective function vector (vector of 45,rows) A = Matrix...

...(Global): Report ID, data= [ 0x01 ] 1 Item(Local ): Usage, data= [ 0xfe ] 254 iProduct Item(Local ): String Index, data= [ 0x02 ] 2 Item(Main ): Feature, data= [ 0x23 ] 35 Constant Variable Absolute No_Wrap Linear No_Preferred_State No_Null_Position Non_Volatile Bitfield Item(Global): Report ID, data= [ 0x02 ] 2 Item(Local ): Usage, data= [ 0xff ] 255 iSerialNumber Item(Local ): String Index, data= [ 0x03 ] 3...

On examining non-linearity of Cox coefficients with penalized splines - I have not been able to dig up a completely clear description of the test performed in R or S-plus. >From the Therneau and Grambsch book (2000 - page 126) I gather that the test reported for "linear" has as its null hypothesis that the...

I'm relatively new to R, but I'm attempting to do a non-linear maximum likelihood estimation (mle) in R, with the added problem that I have a non-linear constraint. The basic problem is linear in the parameters (a_i) and has only one non-linear component, b, with the problem being linear when b = 0 and non-linear otherwise. Furthermore, f(a_i) <= b &lt...

Dear all, can somebody give me some pointer how I can fit a "linear-by-linear association model" (i.e. loglinear model for the ordinal variables) in R? A brief description can be found here 'https://onlinecourses.science.psu.edu/stat504/node/141'. Thanks for your help

Hi all, I would like to test the homoegeneity of variances between several linear model for some analysis of covariance. It seems that the Bartlett's test is a good test to use but I am having problem using with linear model and I cannot find any examples on the internet. There are some examples for comparisons of variances but not linear models. If I take the hellung dat...

Hello, I have done some research about breakpoints (I am not a statistician) and I found out about the breakpoint, strucchange and segmented packages in R allowing to find breakpoints assuming linear model. However, I would like to fit a periodic time series with a non linear (periodic) model, and I was wondering how I could find breakpoints for this model in R. Is it even possible ? My model is an asymmetric gaussian fitting (cf http://www.nateko.lu.se/personal/Lars.Eklundh/Institutionssida/...

Hi, I want to fit a linear model (without any random effect) with method "ml". I tried to use "glm" I found that there is no option for "ml" or "reml" and the default one is "reml". THen I tried to use "lme" but it requires a random effect. How can I fix this probl...

Hi R experts, Could you please help me to fit a linear, cubic and quadratic curve in a figure? I was trying to show all these three fitting curves with different colour in one figure. I spent substantial time to figure it out, but I could not. I have given here a example and what I did for linear, but no idea for cubic and quadratic fitting curve...

the study design of the data I have to analyse is simple. There is 1 control group (CTRL) and 2 different treatment groups (TREAT_1 and TREAT_2). The data also includes 2 covariates COV1 and COV2. I have been asked to check if there is a linear or quadratic treatment effect in the data. I created a dummy data set to explain my situation: df1 <- data.frame( Observation = c(rep("CTRL",15), rep("TREAT_1",13), rep("TREAT_2", 12)), COV1 = c(rep("A1", 30), rep("A2", 10)), COV2 = c(r...

...uring the execution of prgm. we have been succesfull in accessing the interference graph information and creating our version of interference matrix depicting the same information. we then use the same matrix to inspect for its chordal nature. and we are looking for colouring the chordal graph in a linear time using available algorithms. I am looking for material that is related to the above mentioned work that would help me to prepare my report. Particularly i am looking for the information about Linear scan algorithm and PBQP scheme. PLZ do help me out. Thanks, Durga Prasad -------------- next pa...