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# Forum: Statistical Research

Statistical theory and methodology. Mathematical statistics. Parametric inference. Nonparametric inference.

1. ### Sticky: Proof of the day

In this thread we post one (or more if you can't wait) proof a day. I'll start by proving the that V=\sigma^2(X'X)^{-1} in the linear...

• Replies: 14
• Views: 19,432
10-11-2014, 12:02 PM
1. ### Help Anova

hi everyone, I currently try to find an open source C/C++statistical library. Basically, I want to calculate the p and F value from oneway (or N...

• Replies: 11
• Views: 4,779
12-14-2005, 05:55 PM
2. ### Sample size for repeated measures or dependent-sample t

Hi John: I have another question. I collected these data from parents and their children about children's chronic condition. I wanted 100...

• Replies: 1
• Views: 6,729
02-18-2006, 02:27 PM
3. ### Two-tail test

For 1996, the U.S. Department of Agriculture has estimated that American consumers would have eaten, on average, 2.6 pounds of cottage cheese...

• Replies: 1
• Views: 5,904
03-24-2006, 03:02 PM
4. ### EM algorithm

Hello can you help me? I require a program for estimate of parameters in density of mixture exponential With EM algorithm . Thank you for your...

• Replies: 0
• Views: 3,727
04-09-2006, 03:44 PM
5. ### Longitudinal Statistics

I'm performing a longitudinal study on allergen challenged (daily) mice (3 total) where I sample blood from the same mouse daily, over a week's time,...

• Replies: 1
• Views: 2,683
09-08-2006, 08:32 PM
6. ### attrition: comparing *surviving* sample to original

Hi, I have a question about attrition analyses in longitudinal databases. I know that I can compare the subjects who dropped out...

• Replies: 4
• Views: 3,205
11-19-2006, 03:33 PM
7. ### ANOVA without random variables?

I am making a preliminary selection of algorithms to use for recognizing a collection of objects in images. I have a simulation that creates a set...

• Replies: 0
• Views: 2,363
01-08-2007, 09:17 PM
8. ### T scores & a Multivariate Analysis

4 tests were administered to 2 different groups. The scales of measurement for the tests were different, so the raw scores were converted to...

• Replies: 1
• Views: 3,170
05-30-2007, 12:02 AM
9. ### General lasso question

Hi all, I'm using logistic regression with a lasso-like constraint on the parameters. I have noticed that very often the sum of the absolute...

• Replies: 0
• Views: 2,556
06-13-2007, 09:07 AM
10. ### Regression Method

I need to create a software algorithm to calculate cubic or quartic regression on an array of values, but it's been a while since my last stats...

• Replies: 4
• Views: 3,482
06-15-2007, 01:34 PM
11. ### comparing two measurements over time

I'm designing an experiment with two condition. Cond A with no manipulation of the independent var and ConB with manipulation of the independent var....

• Replies: 8
• Views: 8,128
08-27-2007, 04:38 AM
12. ### New guy, Stats help needed with this problem.

Hi guys, I'm taking Mathematical Statistics course and we are following Statistical Inference book by George Casella. I was able to solve most of...

• Replies: 3
• Views: 3,151
10-11-2007, 11:30 AM
13. ### markov chains- estimation

Hello all, my task is to estimate parametres of markov chain model basing on real economic data. Does anyone have any idea what sort of data would...

• Replies: 1
• Views: 2,730
01-12-2008, 10:19 AM
14. ### weibull distribution

i'm studying film life cycle using the weibull distribution. given the survival function, there exists the hazard rate, or the failure rate, a point...

• Replies: 0
• Views: 2,862
02-04-2008, 12:50 PM
15. ### Describing a curve in order to compare with species abundance

Hi, I was wondering if there was an established method / algorithm for describing a curve (in this case, grain-size data) in order to compare...

• Replies: 0
• Views: 3,747
04-11-2008, 05:31 AM
16. ### Impact of static sample on CI

I'll get straight to the question first and then explain it. In a longitudinal study, does having a static sample impact how the CI is...

• Replies: 1
• Views: 2,373
04-24-2008, 08:37 AM
17. ### Weighted EM algorithm?

Hi, I have written an EM algorithm for mixtures of gaussian distributions. However, my problem is that I would now like to "weight" the EM so that...

• Replies: 1
• Views: 4,181
05-01-2008, 11:08 AM
18. ### continuous/categorical IV in anova

Hi, I understand that ANOVA assumes categorical IVs, and ANCOVA should be used if continuous IVs are included in the model. I am currently analyzing...

• Replies: 8
• Views: 15,337
05-23-2008, 08:33 AM
19. ### Partial Least Squares

Hello, I am doing a project about "Partial Least Squares", and I find it a bit hard to understand the math part of the model. I was wondering if...

• Replies: 0
• Views: 3,042
05-24-2008, 11:20 AM

I'm currently working on a project that looks at clustering retail stores on the bases of their Sales performance by item class. Items that are sold...

• Replies: 4
• Views: 3,370
06-03-2008, 07:20 PM
21. ### Constucting ARMA realizations

Given estimates for the AR and MA coefficients for an ARMA(p,q) model with a non zero mean, how do I construct a realization of the time series? ...

• Replies: 0
• Views: 2,985
06-11-2008, 10:26 AM
22. ### Two objective functions in one Unconstrained optimization problem

Think about we have 2 objective functions and both of them are in the form of being equal to zero. For example, maximize f1: x1^2+x1*x2+2*x2^3=0...

• Replies: 0
• Views: 2,688
SPS
06-17-2008, 02:40 AM
23. ### Joint Normal CDF

Hello I am new to this forum as well as to actuary field. I have this question: There are two random variables X_1 and X_2 following standard...

• Replies: 7
• Views: 7,677
06-20-2008, 08:13 AM
24. ### quantile regression vs. non-parametric curve fit of quantiles

hello, i am doing some data analysis using a technique like the one pictured here:...

• Replies: 0
• Views: 2,979
d^2
06-23-2008, 09:54 AM
25. ### Lanczos' Algorithm for Sparse Matrices

I just have a quick question about the implementation of lanczos' algorithm. If you are unfamiliar with it, it can be found at...

• Replies: 0
• Views: 3,175
06-24-2008, 10:44 AM
26. ### Question about copula-GARCH models

Hello everyone, I am learning about copulas and also do some MATLAB coding to get better understanding of how copulas work. Recently I have...

• Replies: 3
• Views: 8,878
06-26-2008, 03:15 AM
27. ### Modeling traffic according to a distribution.

Hello everybody! I'm new in this forum and I hope this is the right place to post this thread.. I'd like to kindly ask you just a suggestion to...

• Replies: 6
• Views: 3,762
06-27-2008, 05:47 AM
28. ### Multinomial logistic regression

I have been carrying out some analysis using multinomial logistic regression and I would like to compare two competing models to see which is the...

• Replies: 2
• Views: 4,103
06-29-2008, 08:07 AM
29. ### Eigenvector for large matrices

Well, this is kind of a linear algebra question, but is used very often in statistics, so it seems applicable for this forum. My question is, does...

• Replies: 11
• Views: 7,211
07-01-2008, 01:58 PM
30. ### Testing Accuracy of Tridiagonal Matrix Computation

So I implemented a lanczos algorithm which tridiagonalizes a real symmetric matrix. However, I don't know if my result is accurate. How would I be...

• Replies: 0
• Views: 3,277
07-09-2008, 09:53 AM
31. ### simultanoues equations for panel data

I want to estimate a simultaneous equations model in which each structural equation has a panel data structure. how to do it? Stata doesn't have a...

• Replies: 0
• Views: 3,588
07-14-2008, 07:46 AM
32. ### Comparing 2 Likert scale with different scale numbers

One of my surveys has a Likert scale of 1-7. The other survey that I am comparing it too has a scale of 0-5. My study is a correlation study, but I...

• Replies: 0
• Views: 10,163
07-18-2008, 01:04 PM
33. ### Weighting by sample size/confidence intervals in regression analysis?

Hello, I am conducting an analysis of how a gene frequency (technically allele frequency) correlates with certain ecological variables (mainly...

• Replies: 0
• Views: 3,989
07-24-2008, 10:33 PM
34. ### Plus-4 Method

Can anyone explain the reasoning behind why the "Plus-4" Method is more reliable? Or, can anyone point me to a resource that explains why? This is...

• Replies: 0
• Views: 11,167
07-25-2008, 08:59 AM
35. ### What test?

HI! Thanks to anyone that is reading this!! I am a masters student and I am trying to figure out what test I should use to analyze some of my...

• Replies: 1
• Views: 2,313
07-26-2008, 10:26 PM
36. ### Longitudinal Data Analysis

Hello people, I need some help with LDA, I have important home work to do and I have a problem. I got autocorrelation of a model: (obs=70) ...

• Replies: 0
• Views: 3,127
07-28-2008, 05:28 AM
37. ### time variables in a regression

Hi all, I'm looking at a linear regression model using the data on wars in the 20th century. There are two time variables on the right-hand...

• Replies: 2
• Views: 7,045
07-29-2008, 12:15 PM
38. ### finding quantiles

how do you find the quantile of a single number in a distribution in R? input: number output: percentage THank you!

• Replies: 5
• Views: 7,696
07-31-2008, 04:08 PM
39. ### need help for my research

Hello ! Two types of people probably lurk on this type of Internet site! The ones who hate statistics and for which numerical logic remains a...

• Replies: 0
• Views: 2,750
08-03-2008, 11:23 AM
40. ### Hypothesis testing

conduct a hypotheses text for each sample at the .01 level of significance and what action should be taken provide the test statistic and p-value for...

• Replies: 4
• Views: 5,608
08-03-2008, 06:52 PM
41. ### negligible trend tests?

Greetings, I'm looking for information on how to test for a "negligible" trend. Info such as links to websites, formula/equations, and other...

• Replies: 4
• Views: 2,968
08-04-2008, 10:43 AM
42. ### Which test to use?

I'm trying to compare one data point to a distribution to see if that one data point fits into the distribution. The distribution is not a normal...

• Replies: 2
• Views: 3,165
08-04-2008, 11:28 PM
43. ### Help needed - estimating effect size

Hi everyone, I'd really appreciate any help/guidance in solving a little problem of mine. I need to know how to estimate an effect size...

• Replies: 3
• Views: 5,043
08-05-2008, 02:00 PM
44. ### Regression Equation

Hi there, Could someone please tell me which values do the following symbols represent in the regression equation: ∆R2 (R Square Change?) ∆F (F...

• Replies: 2
• Views: 19,861
08-10-2008, 08:16 PM
45. ### help on statisitcal test to use

Hi! In my research I am using a surrogate approach (number of surrogates=100) and I making a comparison among indeces (as correlation indeces...

• Replies: 0
• Views: 2,779
08-18-2008, 03:29 AM
46. ### Infinite divisibility under mixing - kernel density estimation

Hi all, Can we consider a (multi-modal) kernel density estimate as a finite mixture of probabiliy distributions which would be infinite divisible?...

• Replies: 3
• Views: 5,136
08-18-2008, 12:07 PM
47. ### Coding Open Ended Questions

Hi, Can anyone tell me where I would begin if I wanted to code some open ended questions? People tell me it's easy, but I don't know; where or...

• Replies: 2
• Views: 9,512
08-19-2008, 10:32 PM
48. ### Factor Analysis Transformations: Thesis Help Needed Please!

Hi I'm really hoping that someone will be able to help me? I am currently in the process of running a factor analysis. The individual items...

• Replies: 1
• Views: 3,264
08-20-2008, 04:06 PM
49. ### What kind of ANOVA is this?

I'm doing an MRI research study on source memory and aging using emotional stimuli. This is probably a fairly basic question, but I'm not sure what...

• Replies: 2
• Views: 2,481
08-21-2008, 12:36 PM
50. ### Clusters - Help!!!!!

Hi unfortunately my stats abilities fall well short of solving this problem properly (it is over 20 years since I finished my Chemical Engineering...

• Replies: 1
• Views: 2,519
08-21-2008, 01:23 PM
51. ### markov chain modelling

Hi guys, Got a complex question regarding markov chain modelling. I'll start off with an example. Say you own a credit card and you can only...

• Replies: 7
• Views: 4,655
08-23-2008, 09:12 PM
52. ### A bit rusty could someone give me a shove in the right Direction Please

Hi guys , I'm a management PhD student. I did a module on SPSS 14 before having to take a year out. I'm now starting to write up a bit of my thesis...

• Replies: 1
• Views: 2,905
08-25-2008, 11:05 AM

Hi, I'm new to the forum, and worried that I have screwed up my thesis project. I thought I designed a standard one group pretest/postest design. ...

• Replies: 1
• Views: 10,664
08-27-2008, 03:34 PM
54. ### Repeated Measures ANOVA with a Continuous Variable?

Hi, I'm trying to run a repeated measures ANOVA. There's a continuous variable that's affecting my data, that I need to control for. I tried...

• Replies: 2
• Views: 9,629
08-27-2008, 04:11 PM
55. ### Factor Analysis Projections

I'm working with some time series data and I'm trying to determine if using factor analysis as a clustering method will lead me to a different...

• Replies: 0
• Views: 2,329
08-27-2008, 10:06 PM
56. ### DOE for Logistic Regression

Hello- Does anyone have any references for DOE (especially multivariate testing / Taguchi) for binary response variables (analyzing with Logistic...

• Replies: 5
• Views: 4,368
08-28-2008, 11:18 AM

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