multivariate analysis

  1. A

    MLR equivalent for repeated measures, multiple correlated responses

    I'd like to determine the best approach to determining effect sizes for a set of experimental data with multiple correlated responses. Due to repeated measurements and high correlation between responses, I know that a simple multiple linear regression model obviously isn't the answer. The...
  2. M

    Choosing factors for principle components analysis

    Hello, I am running a PCA on a dataset that includes 43 water wells, each with up to five descriptive factors associated with it (temp, distance to significant location, depth, number of taxa, volume of flow). I am using XLSTAT to perform the analysis. Running the PCA with the whole...
  3. J

    When to use Multivariable vs. Multivariate?

    Hi - I recently met with a statistician to discuss some of my data, and learned quite a bit, but was still left with some questions. I have learned that there is a difference between multivariable and multivariate data; however, I am not certain when to use each approach. I understand that...
  4. A

    R Test for Significance - ANOVA?

    The Data set; 3 sample types (this includes the control) with 2 treatment types, treatment applied every 2 days for 30 days. I know the 2 treatments will produce different results are am not testing for difference between them, interest is in the three sample types and how they handle a...
  5. B

    Multivariate Survival and Distribution Functions

    Hello, I would like to confirm if the attached relationship between the multivariate survival and the distribution functions is correct. I read elsewhere that in the multivariate case, the equality in the attachment isn't true. Am I missing something? Thank you.
  6. D

    Type I and type II errors in multiple factor ANOVA

    Hello, I wonder if someone can explain to me what happens with type I and type II errors as you add more factors to ANOVA design, specifically to the repeated measures. Thank you.
  7. G

    This is an example of a Nonnrmal Bivariate Distribution with Normal Marginals

    Its a problem set that given to us on our major Multivariate Analysis. But i don't know where and how to start. Any ideas? 4.8 Let X1 be N(0,1) and X2 = { (-X1 if -1 ≤ X1 ≤ 1 or X1 otherwise) . Show each of the following. (a) X2 has also an N(0,1) distribution. (b) X1 and X2 do not have a...
  8. S

    AMMI algorythm

    Hi, Does anyone has experience using AMMI (additive main effects and multiplicative interactions)? If yes, could you please provide practical information on how it works and SAS code that performs the analysis? This is a technique used in multi-location, multi-year plant breeding...
  9. B

    How to analyze data with more than one associated categorical dependent variables?

    I have some dependent variables related to the growth of a company having categories like (e.g. for variables indicating net profit, financial turnover etc.) (1) decreasing, (2) stable, (3) increasing and (4) rapidly increasing. Now these variables are associated and ordinal in...
  10. M

    Multivariate data set of two groups: finding which variables are statistically diff.

    I have a data set consisting of two different groups (A and B) each with 5 specimens. We tested 73 different variables in each specimen and recorded the data. I am new to statistics, so I am struggling to find the best method(s) in which to analyse the data so that I can find which variable(s)...
  11. B

    Does SPSS give standardized factor scores?

    From the Johnson's book, I can see the orthogonal factor model is as follows: X−μ=LF+ϵ So if I use SPSS for extracting factor scores from a factor analysis of several variables, then am I going to get factor scores for mean subtracted variables? Actually my intention is to use the factor...
  12. R

    Combining models into single one

    Yi = B0 + (B1X1,i) + (B2X2,i) + ui Yi = A1 + (A2X1,i) + (A3X2,i) + ui How to formulate these two models as one single linear model using the covariates X1;i; X2;i and X3;i Referring to Hammerbiddle's paper, X1,i has value 1 for below avg and 0 for otherwise. X2,i has value 1 for above avg and 0...
  13. A

    How to prove a non negative definite matrix has to be a variance-covariance matrix?

    I know this is a iff condition,and the reverse is easy to prove.But I am having some difficulty to prove that all non negative definite matrices are variance covariance matrix.From what i have collected from wikipedia,I tried to prove it this way. Let A be a non negative definite matrix...
  14. K

    SPSS - what test to run with MANY different variables

    Hello, I need help deciding what statistical test to run (and advice on how to run properly) for many different variables. In this case the researcher wants to know how demographics influence test scores, there are 6 independent variables (age, gender, years in workforce, etc.) all nominal. Then...
  15. W

    Help with multivariate analysis

    The design specification states that the thickness of the wafers should be 300um and the surface roughness should be 20nm. Is there any evidence that the specification is not being satisfied? Formulate and test a suitable hypothesis. What do you conclude. What have you assumed? Obtain...
  16. E

    How to determine multivariate confidence in laymans terms

    I am trying to determine colors to best grab a web-users attention. I have a simple system which randomly chooses one of 4 foreground colors, and one of 6 background colors. I then save the stats in a table like this: fore_color back_color shown clicked ---------- ----------...
  17. B

    Mahalanobis distance in spss

    please show me how to generate mahalanobis distances using spss
  18. T

    Question about a strange type of variable in Cox regression table

    I have a question about this Cox regression analyse table; If you take a look at the valuation of variables in this table, you will see that some are coded binair (0 or 1). But for some reason the author of this table used for 'tooth type' a valuation from 1 to 6. So my questions are; Is...
  19. M

    [Minitab] question re: Linear Discriminant Function for Groups

    Hi all, In prep for analyzing my MSc dataset (bird breeding and feeding ecology data from the Arctic), I'm trying to understand discriminant function analysis (among other things!). I've digested most of what my biostats text has to say, and have a basic understanding. I've spent today and...
  20. spunky

    On the history of MANOVA's null hypothesis...

    hey everyone! this is kind of a different topic from the "how-to-analyze-my-data" questions, but i think it's kind of relevant. anyways, so my advisor brought in this question in our previous research meeting. it seems like people phrase MANOVA's null hypothesis in two ways: 1. the vector...