Forum: Biostatistics

Hello, I'm trying to do a repeated-measures ANOVA but my data is likely violating the multivariate normality assumption. My question is: Does...

Hi we had 5 investigators 1)hand out 100 surveys and 2)record a certain feature of each of the 100 subjects. That feature that they recorded is the...

Hi everybody. I have two groups of doctors, group A and group B. I'm trying to see if there is any statistical difference between them in their...

Health Economist Introduction This is an opportunity to work for an international company specialising in Health Economics, Patient-Reported...

Compare point estimate to interval estimate

Hi, I'm looking to analyse some vigilance data from monkeys. The data at the moment comes from 5minute samples, but these are separated depending...

Hi, The data I'm looking to analyse is vigilance data from monkeys. I need to investigate which factors affect the different types of vigilance....

Hi We have a set of patients with dental implants in their mouths. We wanna evaluate whether implants in each patient's mouth are as sensitive as...

Problem: I use a common clinical specimen divided equally into two sets with each set to test 3 culture media for growth of a certain organism after...

Does anyone know why there are differences in results when performing Kaplan Meier survival analysis tests in SPSS and SAS. The values do not match...

hi everyone can you help me which test i should use ? purpose is to determine the association of intake of dietary-fiber (3 different types of...

Hi, I am hoping someone can help me with which model (frailty, strata or cluster) I should use for my data. I have paired data so I need to take...

Hello, I have calculated mean concentrations of various environmental chemicals in a population. These chemicals fall into different classes...

Hi My data is on two equal groups of patients. The two groups have roughly equal proportions of males/females. A blood sample was obtained form each...

Hi all, I know nothing about sample size calculations, and always feel that this is an area I am lacking in. In general I work with data that has...

Hi! I am having trouble to decide what statistical test to use on my data because I have one factor grouped within another. Here is my...

Hello, I have data regarding some new blood test. I have a large sample of 450 patients, all healthy, and I would like to characterize the...

Hi everyone, I'm working on analyzing some data right now but I'm not sure if I'm even approaching this correctly. I have a master set of data that I...

Hi, community, I'm trying to solve this issue using free software on Mac OS X and Ubuntu, namely PSPP (SPSS-compatible), Gnumeric, LibreOffice,...

Okay, I have one group of patients. This is a hypothetical example: drug A and B are drugs that decrease puls rate. After application of...

Hi all, I'm investigating the factors that contribute to high or low variability in the greenness index of a grassland area over the course of 10...

Hello, I have retrospective non-randomised data and wish to investigate the relationship between blood transfusions (2 treatment groups :...

Hello, I am trying to better understand how are end points in clinical trials defined when Kaplan-Meier method/log rank test is used. I met this...

Hello everybody, I was wondering about a method to lump a dataset of 20 groups of subjects, each group characterized by a specific mean age, stand...

Hello, I am conducting a basic preference test experiment to determine whether subjects spend a longer time investigating sample A vs. B, and for...

In a meta-analysis looking at the impact of age on the incidence of an adverse outcome following treatment for "X", which effect sizes and...

I have survival and other data for between ~1000 patients from different studies with indications varying from organ transplantation to cancer....

My question concerns a Structural Equations Modeling analysis. Should one be worried about a model being partially, over, or under identified after...

Dear Forum Members and Statistics Ballers! I am currently trying to model a survival function for entrepreneurs, and would like to specifically...

I am designing a RCT between two interventions (two closure techniques of abdomen after an operation) to assess their safety, the safe intervention...

In performing multivariate logistic regression with the WINKS software the output is given as a contingency table with predicted and actual outcomes...

Hi all, I am having some trouble deciding which test to run for a chapter of my thesis. The brief intro is that I felled trees, cut them into an...

:wave: Hello, thank you so much for your help. I am currently working on an article about trends in streamflow in watersheds with different land...

Hi All, I'm thinking about Sens vs Spec, like in the worked example here: http://en.wikipedia.org/wiki/Sensitivity_and_specificity but there...

I am doing a very simple assay to determine if biofilms are reduced when treated with a compound. Every time I run the assay I run an untreated...

Hi everyone, hopefully this is in the right forum. I ran a mixed between-within subjects ANOVA in SPSS to see whether habitat affected the change...

Hi, I've posted a couple times before - hadn't gotten replies but have kept plugging away. I thought I'd give it one more try with updated...

I am analyzing the data from an MRI experiment where we tested a new contrast agent against two control agents in mice with tumors. The experiment...

Ppl I really need help! Please, help me solve it: Consider the model Yi = b0 + b1Xi +ei e_i~N(0,s^2_e) iid X_i_N(m_x,s^2_x) iid Z_i = X_i +...

Hi everyone, I just thought it's easiest if I go through my research plan and the aim to put things into context. I've been told one thing by one...

Hello everyone, I did a study evaluating 2 screening tools (questionnaires) compared to a reference in the same sample of patients. So all the...

Hello, I am interested in comparing proportions between two populations. For example, let's say in one box of 100 marbles there are 20 blues,...

Hello, I am analyzing NAMC and NHAMCS ambulatory health care survey data using SPSS. There are design variables in the data files that can be...

I am planning an evaluation of a health program that is being implemented at 42 health facilities. I will do a quasi experimental study that will be...

Hi, I am exploring SPSS 20 and there is this new option which seems promising: Anomaly Indices, it is in Data>Identify Unusual Cases. To me it seems...

Hi there, I'm trying to find some way to summarize multivariate data so that I can look at interaction terms for entire groups of molecules...

Hello, I have a question. What would be more appropriate when modeling repeated measure experiment depending from 2 groups Y~1+GROUP|ID, labels...

Hello all, I've been breaking my head over the following problem for some time now, but have been unable to solve it. I'm trying to asses the...

Hello, I desperately need some help with my project... If someone could help me, I would be very very grateful! I am comparing the different...

Hi there, I know this is my first post, but tried looking on the forum and couldn't find a specific answer to my question. I'm using SPSS 17 to...