glm

  1. W

    General and generalised linear models

    Hi, I've done a few GLM's with poisson distribution, the code I've used is name<-glm(dependentvariable~independent+independent+independent,family=poisson,data=datset) for some the dependent variable is non-normally distributed so I believe I need to use a generalised linear model. But...
  2. S

    Approximating the probability of an event occuring from the output of a Poisson GLM

    Hi all, I have some data that includes the output of a Poisson Log Link model, that aims to predict how many times an event will occur over the period of a year. I would like to approximate the probability of at least one event occurring from this output, though I am not sure how to go about...
  3. V

    Am I interpreting this correctly?

    I have a continuous DV and 2 categorical + 1 continuous IVs. In spss I did a univariate analysis and found a main effect of one of the categorical ivs and a significant interaction between the two categorical IVs and the DV. I am interested in seeing if there is a three way interaction between...
  4. S

    Comparing fit of GLM to OLS regression

    Hello talkstat. First post in this magnificent forum! In my master thesis I'm estimating health care expenses to patients, who has experienced a occupational injure on administrative data. The depended variable is total health care expenses for a given individual a year after the...
  5. V

    p-value for logistic regression

    How do I find the p-value for logistic regression. For example , for a glm output I : z -value : 1.32 P ( > | Z | ) = 0.186696 If it were a normal regression would do : 2 ( 1 - P ( < | Z | ) = 2 (1-0.4066) = ??? The t-value = Estimate/ Std.Error...but P(>|t|) i don't understand.
  6. R

    What GLM family if response is Bray-Curtis dissimilarity? Can I use adonis (vegan)?

    I have some questions about testing for effects of different experimental levels on community similarity. I'll explain my planned experimental design before I ask the questions: I have two methods for sampling species. I will use both of these methods on the same vegetation patch, at 3 points...
  7. C

    Hypothesis difficulty

    Let Y_{ij}=1 if the i^{\text{th}} child is classified as obese at the j^{\text{th}} occasion, and Y_{ij}=0 otherwise. The marginal probability of obesity at each occasion follows the logistic model log\frac{\Pr(Y_{ij}=1)}{\Pr(Y_{ij}=0)}=...
  8. V

    Which Analysis is Correct? (if any)

    Hi! I have a design with two categorical iv and one continuous iv with a continuous dv. I wanted to see if there was a main effect or interaction from the categorical ivs, so I used the syntax: glm DV by IV1 IV2. There were no significant interactions or main effects. I wanted to then add...
  9. E

    MSE in GLM ANOVA

    Sorry for the wall of text, but I'm trying to figure out how to proceed and feel as though I need to clue you in as best I can. Experimental Design: Whole plot: Tree species (Spp) Subplot: Location relative to canopy boundary (In/Out) Tests: 2-way ANOVA on data collected for several...
  10. N

    Plotting the results of GLM in R

    I have this data plotted as a scatter plot in Excel I had done a regression in Excel, and the p value was 2.14E-05 while the R- value was 0.32. I was told the R value was too low compared to the significance of the p value, and was told to control for the dispersion of the data by running it...
  11. H

    Transform data for factorial two-way ANOVA/General Linear Model??

    Hi, I'm not very statistically minded but I would really appreciate some guidance. I am needing to do several stat tests for my MSc dissertation. I have one dependent variable (species count) and one independent variable (year), but two species. I have constructed a basic count against year...
  12. H

    Repeated measures design - correct analyses and GLM assumptions

    Hi all, I have collected data for a study but I am not sure now if I am carrying out the correct analyses. I have tried for the last few days to figure out whether my analyses are correct, but I keep getting a lingering doubt that they are not and so I thought I will ask this question because...
  13. O

    Indices with data bound between -1 and +1

    Hi all, I would really appreciate some advice on how to deal with my data. I would like to compare data calculated from an index which is bounded by -1 and +1. I was surprised to see that previously published use of this index has been analysed using standard ANOVA, because I was led to...
  14. E

    Help with glm--- Simple Logistic Regression

    Hi All! Thanks for reading. I wanted to compare month of sample collection (April, May, June, and July) to presence/absence data (coded in binary dummy variables). I tried to run a Simple logistic regression, but realized that the output table with p values, etc all report for may, June, and...
  15. I

    GLM in SPSS

    Hi, I am trying to do something quite simple but I am so confused about how to enter my data into SPSS and which test to use. I have four subjects whose performance is measured at ten time points and I want to know if their scores are changing. Normally I would enter my data with one subject...
  16. A

    Fixed term is “(Intercept)” --Dredge function

    Hi, i'm currently running a glm model in R and have attempted to use the following code: Model: resultsnew<-glm(R0A1~MP_Perc+MPHW_Perc+HW_Perc+YP_Perc+AG_Perc+Shrub_Perc+Dist_CountyRoad+Dist_PrimaryRoad+Dist_SecondaryRoad+Dist_TertFireRoad,data=secondorder,family=binomial("logit"))...
  17. T

    Help with model Matrix GLM

    Hey guys been browsing the forums for a while, and usually find what I need! This is a tad more specific though so Ive made an account!! I've been puzzled by the form of the model for a while.. The model states that the response depends upon y~smoke + drink +smoke:drink +age:smoke. The model...
  18. A

    Binomial response variable with 3 continuous and 1 categorical predictor. Best test?

    Hello I have a binomial response variable. Predictors are composed of 3 continuous variables (the results of a Principle Components Analysis of habitat structure variables) and 1 categorical variable (habitat type e.g. grazed or ungrazed). I want to test whether the 3 habitat variables have...
  19. B

    Type I and Type II SS for ANOVA, non-statistician

    Good Afternoon (non-statistician here), I have to automate a GLM within an Excel sheet that will be analyzing some toxicity data, resulted from scoring cell aberrations. And, I'm using MiniTab to validate the estimates. MiniTab is using Type I (sequential) SS and Type II (adjusted) SS within...
  20. J

    How to model weighted average ratios in the [0,1] interval

    Maarten Buis on this forum provided great insight on how to model percentages in the [0,1] interval (http://www.talkstats.com/showthread.php/52986-Modelling-percentages-in-the-closed-interval-0-1). I now have a similar but somewhat different problem, in that I'd need to model weighted average...