stepwise

Hello, What are the criteria for computing the pairwise or the stepwise step-down comparison in SPSS after Kruskal-Wallis? I know that the pairwise comparison is more conservative than the stepwise comparison, but are there any other criteria to decide which post-hoc test to use? Does anybody...

I've recently been working on building a model and have come across a number of different approaches. I'm particularly interested in the limitations of using Stepwise regression as it has a huge amount of criticism online, however I can't find much material detailing why it's a poor method to...

I have derived a statistical prediction model using backwards stepwise logistic regression in SPSS. There are 5 independent variables which predict mortality, one of which is age (the other 4 are binary variables). I have decided to dichotomise age so that the score can be easily used. I...

Hi all, I need to perform logistic regression for my study. Pretty new to it but have read up on it and have tried it on SPSS. I would like to seek the advice from all of you regarding it. A brief description on my study: I want to see which factors (categorical and continuous) are...

Hi, I have 20 independent variables and 1 dependent. I've used the stepwise method to determined what predictors are more significant compared to other predictors and I ended up with 10 statistically significant predictors. However, I am not sure how check if a nonlinear multiple...

Hi, I want to do a multiple regression analysis. I have one Y which are numeric values (sample number = 85) and the following Xs. Sr No Variable Data type Data example 1 Region 4 factor levels Region ABC 2 Class 3 factor levels...

Hi everyone, I am working on gene expression data for 15 genes and am supposed to derive a minimal predictive set of genes that can be used as a marker profile for disease progression. So far, I created Kaplan-Meier curves for all 15 candidates and performed tested for association with bad...

Hi! I am performing a linear multiple regression analysis in spss in 3 steps. In step 1 I entered my control variables (2 interval and 4 dummy variables) using ENTER as the method. In step 2 I entered my 4 dichotomous independent variables, again using ENTER as the method. Finally, in step 3 I...

Hi all, i am using the stepclass function which is part of klaR package. I have everything running just fine using a stopping criterion based on improvement of the performance measure. However, now i want to run stepclass and stop when the "best" r variables have been found even if the...

Hello Everyone! I am a very new member to the forum, and extremely glad to find this lively discussion environment. I am a post-doc in astronomy, and with not that profound statistical background. I have come up with a bottleneck that like to consult with experts. So, let me introduce my...

Hello, I have a large pool of candidates to choose from to perform a stepwise regression. I did some research and found that the R function "step" or "stepAIC" basically uses "add1" and "drop1" to select or drop a variable. This becomes VERY slow when I have more than 50 variables already in...

Hi all, I have run both hierarchical and stepwise methods on my data with 34 IVs (categorized under 7 groups of variables), using SPSS. The hierarchical regression allows these 7 groups of variables to be entered in the order that I want, and the SPSS output shows a coefficient table which...

I am in the process of evaluating the importance of some factors in predicting stock returns. In this context, I would like to implement the forward stepwise regression methodology. My dataset is comprised of 13,000 securities with monthly data from 1984 to 2012. Since this is my first...

Hi all, I have a conceptual model, with different covariates to explain an o=e relationship. I have confounders and effect modifiers. I am unsure, to begin the manual forward selection (for which I will only add variables based on certain criteria), with covariates CLOSER to the main...

Hi, Having researched stepwise regression there is a clear view that you need to target a Case:IV Ratio of at least 40:1 as "stepwise doesn't generalize very well beyond the sample"... given that I'm looking at running some employee surveys and I suspect the response is going to be very high...

Hello all. I need a little help in translating SPSS language into R. In SPSS, you can run stepwise regression by entering them into "Blocks" (which I believe is analogous to steps). Unlike R, which determines which single variables to add or subtract depending on the AIC, SPSS allows to...

Hello, I have preformed a stepwise regression on my data set using SPSS. In the out put table the "R Square Change" value for the second model is larger than the "R Square Change" value for the first model. I am not sure why that is. I was expecting SPSS to output the model with the...

I have a specific question: when running a stepwise Discriminant analysis, if I get 2 or more steps, and then SPSS shows the eigenvalue of "function no. 1" ONLY which explains 100% of the variance, does this mean this function includes the variables in all of the steps? So, for example, I...

Howdy, The attached spreadsheet contains the correlation matrix of predictor variables and response variable. Correlation exists between them. Additionaly included are the results from a Principal Components Analysis on my (scaled) predictor variables. I used the prcomp command in R with the...

When a variable is added and then removed in stepwise regression, what happens to the proportion of the variance it explained?