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Threads 841 to 900 of 1890

Forum: Biostatistics

Epidemiology and biostatistics, public health research. GLM, logistic regression, survival analysis, clinical trials.

  1. correction for multiple testing with unqueal sample sizes

    Dear Sirs, I perform several thousand tests on a genomic dataset (Mann Whitney U test). However, there is great variability in the sample size for...

    Started by MARijlaarsdam‎, 11-19-2013 04:58 AM
    • Replies: 0
    • Views: 1,968
    11-19-2013, 04:58 AM Go to last post
  2. dependent or independent

    Dear Sirs, I have situation in which I query different sites on the genome (biologically independent) and for each site I get a measurement. I...

    Started by MARijlaarsdam‎, 11-19-2013 04:47 AM
    dependence, independence, sample
    • Replies: 0
    • Views: 1,229
    11-19-2013, 04:47 AM Go to last post
  3. Meta-analysis: comparing effect sizes

    I am conducting a systematic review to compare the effect of intervention A vs. B on outcome Y (A, B, Y binary variables). So far the collected...

    Started by tiffanyjung‎, 11-16-2013 05:33 PM
    • Replies: 0
    • Views: 1,276
    11-16-2013, 05:33 PM Go to last post
  4. Measuring association between an ordinal variable and presence or absence of an event

    Hi everyone, I have done a research project measuring the severity of tortuosity of iliac arteries in patients who underwent EVAR (Endo Vascular...

    Started by ramakrishna_16‎, 11-15-2013 05:27 PM
    association, severity, significant association
    • Replies: 0
    • Views: 1,012
    11-15-2013, 05:27 PM Go to last post
  5. Using Mann Whitney U to verify relation between analitical values and mortality

    Hello! I'm new to the forum, and currently trying to do a paper on a retrospective study I did. I don't have much knowledge in statistics, and I...

    Started by tenrousei‎, 11-15-2013 04:15 PM
    • Replies: 2
    • Views: 969
    11-15-2013, 04:57 PM Go to last post
  6. Multiple studies all showing p < 0.05 (NOT asking about multiple testing)

    Intuitively, we are more confident in a result if multiple methods or research groups all show the same thing. So my question is: if 5 independent...

    Started by atchen‎, 11-15-2013 02:51 PM
    • Replies: 1
    • Views: 1,503
    11-15-2013, 03:13 PM Go to last post
  7. dependent samples & correction for multiple testing

    Dear all, I have situation in which I compare many genomic regions between two or more cell lines (CL). Each region is covered by n probes...

    Started by MARijlaarsdam‎, 11-15-2013 10:56 AM
    dependence, independence, multiple-comparisons
    • Replies: 0
    • Views: 1,623
    11-15-2013, 10:56 AM Go to last post
  8. Sample Size calculation for a survey

    I want to calculate the sample size for a survey to evaluate maternal risk perception of disease and its association with vaccination status. So the...

    Started by Nijika‎, 11-14-2013 11:54 PM
    • Replies: 0
    • Views: 1,616
    11-14-2013, 11:54 PM Go to last post
  9. error rate reduction analysis

    Hi there, I'm hoping you can help. I'm setting up a small scale study looking at an intervention to reduce drug prescription error rates. I will...

    Started by simfellow‎, 11-13-2013 05:26 PM
    • Replies: 0
    • Views: 1,454
    11-13-2013, 05:26 PM Go to last post
  10. parial likelihood statistic distribution

    Hello, everyone! I am running stepwise variable selection for a Cox proportional hazards model and use log-likelihood test statistic for that....

    Started by dandy‎, 11-09-2013 11:41 AM
    • Replies: 0
    • Views: 1,367
    11-09-2013, 11:41 AM Go to last post
  11. Comparison of average values of data sets

    Hi, I want to know if mean of A>B and A1, A2 are the two subsets of A. Similarily, B1, B2 are two subsets of B. Is the condition A1<B1 and A2<B2...

    Started by Suneyna‎, 11-08-2013 01:22 AM
    average, distributions, pdf, subset
    • Replies: 2
    • Views: 1,960
    11-09-2013, 01:07 AM Go to last post
  12. Time-dependent variables questions

    I've been asked to comment on a retrospective cohort study and I have a bit of a dilemma. Participants in the cohort had the option of receiving...

    Started by thirty006‎, 11-08-2013 01:57 PM
    • Replies: 0
    • Views: 1,039
    11-08-2013, 01:57 PM Go to last post
  13. HELP jmp age adjusting/normalizing

    How can I normalise or adjust for age in jmp???? :shakehead I am attempting to compare independent variables across genders but their mean age is...

    Started by macanano‎, 11-07-2013 06:09 AM
    • Replies: 0
    • Views: 1,867
    11-07-2013, 06:09 AM Go to last post
  14. Help to figuring out an state assignment

    Hi all. I have a problem in one of my assignments and hoping some of you can help. 1) Describe and compare the risk of not having registered...

    Started by axel‎, 11-05-2013 03:21 AM
    • Replies: 0
    • Views: 1,442
    11-05-2013, 03:21 AM Go to last post
  15. Variance estimation with repeated measures

    Hello all, I have data from a continuous variable, I have 47 data points. These data points comes from 20 subjects. Some contributed 2 data...

    Started by NN_STAT‎, 11-04-2013 06:12 AM
    • Replies: 0
    • Views: 1,275
    11-04-2013, 06:12 AM Go to last post
  16. Repeated measures and nested design

    I need to compare groups from a repeated measures design experiment. Unfortunately I had no say in the design of the experiment. Number of blood...

    Started by G.J.E‎, 11-04-2013 05:10 AM
    • Replies: 0
    • Views: 2,618
    11-04-2013, 05:10 AM Go to last post
  17. ANOVA or Kruskal Walli

    Hi! I have measured respiration in 3 treated and one untreated control cell line with N= 27, 25, 31 & 31. Can I use a one way anova or should I...

    Started by jajamensan‎, 10-28-2013 08:30 AM
    anova, biology, cells, kruskal wallis
    • Replies: 4
    • Views: 2,378
    11-04-2013, 04:32 AM Go to last post
  18. Distinguishing noise (batch variation) from true differences

    Hello, I carried out a screen for 400 different genes. This was done in batches of 20 genes. Each batch includes 2 replicas of an internal...

    Started by jrbluebox‎, 11-01-2013 06:27 AM
    group comparison, noise, pca analysis
    • Replies: 0
    • Views: 1,709
    11-01-2013, 06:27 AM Go to last post
  19. Stratified log rank vs cox regression

    Hello everyone, I am performing a survival analysis to compare survival with two treatment regimen (with SPSS). With Log-rank p value is...

    Started by gokhan‎, 10-26-2013 09:23 AM
    cox regression, kaplan meier survival
    • Replies: 2
    • Views: 4,372
    10-31-2013, 03:41 PM Go to last post
  20. Sas, gowers, cluster help

    I am a graduate student new to SAS. I have a data set of skeletal remains and genetic traits on their bones. I need to import the data, then use...

    Started by egwilson‎, 10-30-2013 04:10 PM
    • Replies: 0
    • Views: 1,861
    10-30-2013, 04:10 PM Go to last post
  21. Anything but Multinomial Logistic Regression

    We have 5 mutation sites we are studing in 200 insect species. There are only 20 different mutation combinations among the 5 sites. Each mutation...

    Started by jairo‎, 10-30-2013 11:56 AM
    categorial analysis, logistic regression, xi squared test
    • Replies: 0
    • Views: 1,547
    10-30-2013, 11:56 AM Go to last post
  22. Compare coefficients across Cox regressions to conclude x1 is more harmful than x2?

    Hi, Our question is regarding to comparison of effects of different variables in survival analysis. Usually, the Cox model tests the effects...

    Started by sha_sha‎, 10-29-2013 03:46 PM
    compare coefficients, compare exp(b), cox regression, time-dependent
    • Replies: 1
    • Views: 1,857
    10-30-2013, 03:22 AM Go to last post
  23. Markov Modelling for Disease Progression Help

    Hey guys, I'm using a longitudinal data set to build a multi-state markov model in order to eventually calculate life expectancy for patients...

    Started by DiseaseProgression‎, 10-29-2013 05:54 PM
    • Replies: 0
    • Views: 1,408
    10-29-2013, 05:54 PM Go to last post
  24. What test to use for correlating variables measured for 50 subjects/5 months?

    Hi, I have a dataset that consists of several continuous variables that are measured at months 1, 2, 3, 4 and 5. I have a total of 50 subjects....

    Started by fidel‎, 10-28-2013 10:22 AM
    • Replies: 0
    • Views: 2,273
    10-28-2013, 10:22 AM Go to last post
  25. alpha in one sided tests

    hello all, i have a theoretical question, i have found out that on medical research, when performing a one sided test (instead of the preferable...

    Started by WeeG‎, 10-26-2013 02:59 AM
    • Replies: 5
    • Views: 9,586
    10-27-2013, 08:22 AM Go to last post
  26. Logistic regression and predictions

    I'm looking to do logistic regression in R with a response variable 'diagnosis' which describes if a patient is of class 0 or class 1. I have 3...

    Started by Sheddie‎, 10-22-2013 08:54 AM
    • Replies: 3
    • Views: 2,620
    10-22-2013, 11:24 AM Go to last post
  27. Propensity score matching in STATA

    Hi guys! I need help with propensity score matching in STATA using the command psmatch2. I estimate the propensity score using the command pscore ...

    Started by mcgiglio86‎, 10-21-2013 03:01 PM
    • Replies: 0
    • Views: 3,983
    10-21-2013, 03:01 PM Go to last post
  28. general linear regression?

    Hey there. I would really like some guidance on this. I need to analyse some data. It was collected on a football team playing against their rival...

    Started by Fuerty‎, 10-20-2013 03:26 PM
    • Replies: 2
    • Views: 1,547
    10-20-2013, 04:39 PM Go to last post
  29. Multivariate power analysis?

    Hello all, sorry to forgo introduction and bombard you with a query as my 1st post, but I'm running short of time and it only just occurred to me to...

    Started by Ex_LionTamer‎, 10-20-2013 02:23 PM
    • Replies: 0
    • Views: 1,497
    10-20-2013, 02:23 PM Go to last post
  30. Sample size for a paired t-test

    Hello all I have a simple question. I need to calculate a sample size for a study that will be analyzed with a paired t-test. One of the input...

    Started by NN_STAT‎, 10-17-2013 05:54 AM
    • Replies: 6
    • Views: 3,921
    10-17-2013, 08:18 AM Go to last post
  31. Calculate eta squared for two-way repeated measures ANOVA

    Hi everyone! I did a mixed two-way repeated measures ANOVA. I have an error for the within-subjects (where factor 1 and the interaction...

    Started by juacochero‎, 10-16-2013 08:40 AM
    • Replies: 0
    • Views: 2,747
    10-16-2013, 08:40 AM Go to last post
  32. Red face Continuous variable and its effect on dependent categorical variable, Which test?

    Hi, I question as a new SPSS user (I use version 20) I want to find a relation/correlation/association between an independent continous parametric...

    Started by ahmedhassan‎, 10-14-2013 06:38 PM
    • Replies: 12
    • Views: 3,034
    10-15-2013, 06:53 PM Go to last post
  33. Comparing two groups of cells - Which test to use?

    So I have a project to compare the formation of junctions of two groups of cell lines - a normal and a mutated one. I have number of junctions formed...

    Started by SM1374‎, 10-08-2013 01:57 PM
    anova ecology biology, biological statistics, t test
    • Replies: 1
    • Views: 1,609
    10-12-2013, 11:41 PM Go to last post
  34. Question Analysis of pre-post ordinal data

    Hi everybody, I'm stuck in a problem with ordinal data analysis. We have x patients treated, and two measurements of pain (before/after treatment)...

    Started by junkerj‎, 10-11-2013 12:48 PM
    • Replies: 1
    • Views: 3,105
    10-11-2013, 02:03 PM Go to last post
  35. Need Complex Ordinal Analysis

    My question outlines the need for a non-parametric analysis of ratio data. I have a data set composed of apnea counts for individual mice during...

    Started by ishpeming‎, 10-09-2013 07:35 PM
    multi-factor model, non-parametric
    • Replies: 8
    • Views: 2,104
    10-10-2013, 09:46 PM Go to last post
  36. ANCOVA/MANCOVA vs. Mixed models

    Iíve been asked to consult on a study that is essentially a case-control study. The researchers matched cases and controls on 3 variables. The...

    Started by thirty006‎, 10-10-2013 11:20 AM
    • Replies: 1
    • Views: 2,064
    10-10-2013, 11:30 AM Go to last post
  37. What to do with my data when there is no response variable?

    My research question: which habitat abiotic factors are most important in the distribution of species A. Species A seem to have disjunct...

    Started by ndafuda‎, 10-10-2013 05:05 AM
    • Replies: 1
    • Views: 1,059
    10-10-2013, 07:01 AM Go to last post
  38. multivariate analysis?

    I need to run a statistical analyis to determine which variables are associated with outcome. its medical study outcomes like alive/dead, and...

    Started by edmundfitz‎, 10-01-2013 03:07 PM
    • Replies: 3
    • Views: 1,896
    10-04-2013, 05:10 PM Go to last post
  39. missclassification in estimating proportions

    Hi Assume that I want to compare two methods, say skinfold measurement and BMI, in how they classify subjects into four categories. In a 2x2 table...

    Started by pattebegga‎, 10-02-2013 02:08 AM
    • Replies: 0
    • Views: 1,611
    10-02-2013, 02:08 AM Go to last post
  40. specificity and sensitivity..Please help

    Hi there, I have the following question A new test for cancer is evaluated. We have 1000 subjects. Amongst the group known to have cancer (598...

    Started by adam86‎, 10-02-2013 12:10 AM
    • Replies: 0
    • Views: 988
    10-02-2013, 12:10 AM Go to last post
  41. Post Rank ordering - basic analysis

    Hi, I'm doing a study that has the participant rank 11 items in order of importance to him/her (rank ordering / closed pile sort), with 100...

    Started by Romic1‎, 10-01-2013 06:02 PM
    biostatistics, rank order data analysis
    • Replies: 1
    • Views: 1,066
    10-01-2013, 08:43 PM Go to last post
  42. Smile conversion of non parametric values to parametric ones

    Dear all :) , I'm doing a biological research on vegetative propagation of tree species 'A'. As observations I get both parametric (eg: root...

    Started by Geeny‎, 10-01-2013 12:00 PM
    • Replies: 2
    • Views: 1,283
    10-01-2013, 12:53 PM Go to last post
  43. Question Exponential qPCR values and calculation of Error

    Hi I'm hoping that one of you may be able to help. I'm currently trying to present some qPCR data (for those not familiar with this it measures the...

    Started by lise2709‎, 09-27-2013 09:25 AM
    error bars, qpcr
    • Replies: 0
    • Views: 1,108
    09-27-2013, 09:25 AM Go to last post
  44. Question Checking stat. significant difference between combined measures of performance

    Hello! I wonder how to check is there statistically significant difference between my combined measures of performance of diagnosis methods. But...

    Started by franc_fisher‎, 09-26-2013 11:18 AM
    • Replies: 1
    • Views: 917
    09-26-2013, 03:28 PM Go to last post
  45. Repeated measures ANOVA with intra group factor ? Which model to use ? Clinical trial

    Hi, I have a question concerning the model I should use for my experiment: Presentation of the experiment: I have two groups of children: 12...

    Started by aure95‎, 09-24-2013 10:21 AM
    • Replies: 0
    • Views: 1,781
    09-24-2013, 10:21 AM Go to last post
  46. Which statistical test? GEE?

    Hello! I'm currently playing which my data and am unsure about the statistical test to use. I have MRI data from 25 patients. I have 4...

    Started by PenguinM‎, 09-24-2013 07:49 AM
    gee, glm, statistics
    • Replies: 0
    • Views: 1,562
    09-24-2013, 07:49 AM Go to last post
  47. How would you analyze this ?

    Hello all I have a relatively simple case, however tricky. I am testing a new treatment vs a control. This is a new treatment that you do on...

    Started by NN_STAT‎, 09-24-2013 12:43 AM
    • Replies: 6
    • Views: 1,930
    09-24-2013, 05:00 AM Go to last post
  48. Need help with the right statistics test

    Hi, I am trying to compare two groups of women having distinct breast cancer characteristics: Cancer Group A Group B...

    Started by codudi‎, 09-24-2013 01:50 AM
    • Replies: 0
    • Views: 1,352
    09-24-2013, 01:50 AM Go to last post
  49. Fisher's exact test - relationship to OR CI, RR CI

    Hello, I'm very amateur in statistics, and I'd be thankful for helping me with these questions. We're studying a gene, whose alleles (A, B, C) can...

    Started by majeeda‎, 09-20-2013 08:42 AM
    • Replies: 2
    • Views: 2,975
    09-23-2013, 03:41 AM Go to last post
  50. Significance of change after treatment application

    Hi all, I'm facing a statistical problem much greater than my basic statistics knowledge. I am trying to determine if a change in the...

    Started by dbonicelli‎, 09-19-2013 01:38 PM
    • Replies: 2
    • Views: 1,509
    09-20-2013, 01:26 PM Go to last post
  51. Display range from discrete data

    Quick statistical/mathematical question. I have generated data on lethal dosages in several of my experiments. I would like to create a chart showing...

    Started by mas_snp‎, 09-17-2013 08:59 PM
    • Replies: 6
    • Views: 1,829
    09-18-2013, 10:35 PM Go to last post
  52. evaluation of treatment efficacy in a cohort of people considering a single variable

    Hello, I have to evaluate the treatment efficacy in a cohort of people over a year (so I have 4 groups of data, one for each 3 months) considering a...

    Started by Rerun‎, 09-15-2013 01:53 PM
    • Replies: 8
    • Views: 2,091
    09-18-2013, 05:55 AM Go to last post
  53. Variance components on logit scale

    Hello all, I have data with a binary response (0,1), a categorical independent variable with 3 levels (treatment i.e. an experimental treatment...

    Started by NN_STAT‎, 09-17-2013 03:39 AM
    • Replies: 1
    • Views: 2,405
    09-17-2013, 03:49 AM Go to last post
  54. Need help with sample size calculation

    I need to see if there is significant difference in the outcome rates between 2 groups.How do I calculate the sample size for 80% power.

    Started by psoas‎, 09-16-2013 10:37 AM
    • Replies: 0
    • Views: 1,431
    09-16-2013, 10:37 AM Go to last post
  55. Question on Effect modification analysis

    Dear All I wonder if you kindly would assist me on the basic concept in examining the effect modification. The live example is: I want to analyze...

    Started by drmohamedbekheit‎, 09-12-2013 08:21 AM
    • Replies: 3
    • Views: 2,412
    09-16-2013, 08:45 AM Go to last post
  56. Comparing groups - repeated measures or n-way anova?

    Hello. I'm new to this site as well as to statistics. So, please forgive me if I have posted in the wrong place. I have a project where I measured...

    Started by jeebne‎, 09-15-2013 05:48 PM
    repeated measures anova
    • Replies: 0
    • Views: 1,024
    09-15-2013, 05:48 PM Go to last post
  57. Question Is a 3-way ANOVA, an ANCOVA, or a linear regression best for my dataset?

    I've performed an experiment in which a cell line was treated with a cocktail of three different compounds (call them A, B, and C). Compound A was...

    Started by lnhstats‎, 09-13-2013 02:34 PM
    ancova, anova, linear regression, three ivs
    • Replies: 0
    • Views: 1,429
    09-13-2013, 02:34 PM Go to last post
  58. Pre/Post Comparison of Percentages, Two Populations

    I would like assistance in selecting tests for two scenarios. I am simplifying a bit here, but basically I want to do a comparison of the percentage...

    Started by jdub‎, 09-12-2013 04:18 AM
    chi square test, percentage, pre and post
    • Replies: 4
    • Views: 4,886
    09-12-2013, 08:08 AM Go to last post
  59. Linear piecewise spline interpretation

    Hello, I suspected my data was non-linear so I ran PROC GAM to visualize my age variable relative to my binomial outcome. I realize adding one...

    Started by tsalek‎, 09-04-2013 01:55 AM
    linear spline, log binomial regression, prevalence ratio, sas
    • Replies: 2
    • Views: 2,132
    09-09-2013, 08:54 PM Go to last post
  60. Not sure if ANCOVA or multivariable linear regression is best

    Iím using SAS to analyze data for a quality of life (QoL) project and Iím trying to answer two research questions. I want to present something simple...

    Started by Porter‎, 09-08-2013 04:30 AM
    • Replies: 0
    • Views: 1,348
    09-08-2013, 04:30 AM Go to last post

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