1. 10-14-2010
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Forum: Biostatistics

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

  1. Need Help: Kaplan Meier analysis

    Hi I have a large database and have generated KP curves for long term survival but there is not difference in overall/long term survival. Our goal...

    Started by survivinganalysis‎, 11-28-2015 12:07 AM
    • Replies: 1
    • Views: 112
    11-28-2015, 02:56 AM Go to last post
  2. Appropriate p-value correction in two cohort meta-analysis (discovery / validation)

    Dear all, I would like to request your help and opinions on a meta-analysis setup utilizing two completely independent cancer cohorts, where one...

    Started by bontus‎, 11-26-2015 10:31 AM
    dataset integration, fdr, meta analysis, p-value correction, validation
    • Replies: 0
    • Views: 96
    11-26-2015, 10:31 AM Go to last post
  3. Does this graph shows a normal distribution ?

    Hello, I am a newbie in Biostatistics field... I would be so thankful if you tell me if below chart has a normal distribution or not and why ? ...

    Started by A.Chakery‎, 11-21-2015 03:16 PM
    • Replies: 2
    • Views: 250
    11-21-2015, 06:56 PM Go to last post
  4. Analysis for progression free survival (PFS), and Dose intensities effect on PFS.

    Hi every Body, The project that we are doing is related to a drug that is given to patients having colorectal cancer, after they have failed all...

    Started by sanaullah92‎, 11-18-2015 08:11 PM
    progression free survival
    • Replies: 0
    • Views: 191
    11-18-2015, 08:11 PM Go to last post
  5. Spearman partial correlation corrected for multiple comparisons

    Hi all, I would like to ask you some help about this: Which would be the Bonferroni correction for a Spearman partial correlation controlled by...

    Started by purkinje‎, 11-17-2015 10:27 AM
    spearman bonferroni
    • Replies: 0
    • Views: 142
    11-17-2015, 10:27 AM Go to last post
  6. Data Analysis for Clinical Trials

    For a research module, for my postgraduate degree, I need to design a clinical trial research protocol. I am looking at how safe and effective drug X...

    Started by Joseph551‎, 11-15-2015 02:03 PM
    • Replies: 3
    • Views: 261
    11-16-2015, 03:28 PM Go to last post
  7. Help concerning random forest in R

    Working on a data set with bio markers. This is a classification problem and I'm having some troubles finding any information concerning the process...

    Started by lukketotte‎, 11-16-2015 10:43 AM
    • Replies: 0
    • Views: 109
    11-16-2015, 10:43 AM Go to last post
  8. Need help with spline for clustered data

    Hello everyone, I am a new member on this forum. I am recently running into a problem with analyzing correlated data for a twin study. I am...

    Started by Tiny‎, 11-10-2015 07:19 AM
    • Replies: 0
    • Views: 198
    11-10-2015, 07:19 AM Go to last post
  9. Multiple groups, comparing healthcare costs, problem: excluding specific data [Prism]

    Hi I have cost data for three groups of patients and we want to see if there is a difference in costs before, during and after we implemented a...

    Started by moeveleigh‎, 11-08-2015 08:42 AM
    • Replies: 0
    • Views: 208
    11-08-2015, 08:42 AM Go to last post
  10. Treatment-experiment interactions in multivariate data

    I have a data set of multivariate data (4 treatments, 3 samples per treatment, 14 variables, the variables are concentrations of different...

    Started by Tabita‎, 11-06-2015 04:26 AM
    f-test, multivariate analysis, multivariate data, repeated experiments
    • Replies: 0
    • Views: 170
    11-06-2015, 04:26 AM Go to last post
  11. I need help to analyze this data

    Dear valued experts, I need help in calculating the significance of the following data: Two groups of patients on Rx (A) and (B) I am comparing...

    Started by farahi‎, 11-04-2015 06:35 AM
    • Replies: 0
    • Views: 194
    11-04-2015, 06:35 AM Go to last post
  12. Help! Nursing statistics- wordy problem no one in the class can answer

    Hi everyone! Hoping someone is able to help guide me and my classmates. Our teacher isn't great and will not assist us with this question. Our...

    Started by nursestatsdummy‎, 10-31-2015 12:03 AM
    • Replies: 1
    • Views: 275
    10-31-2015, 12:34 AM Go to last post
  13. What test to run ?

    Hi everybody! I have a small sample of patients that have undergone two interventions and we want to analyze the effect on a specific bloodsample...

    Started by Cak024‎, 10-29-2015 08:25 AM
    • Replies: 0
    • Views: 187
    10-29-2015, 08:25 AM Go to last post
  14. Sample size

    Hello! I need your help to define the sample size of a study. We want to study the effect of a food on the expression of a series of microRNAs...

    Started by Fischer‎, 10-28-2015 08:12 AM
    • Replies: 2
    • Views: 228
    10-29-2015, 05:20 AM Go to last post
  15. Question Pearson's Correlation _ with individual X error and Y error

    Hi all, I have a problem that I can't seem to solve. I don't know how to account for the individual measurement error in a Pearson's correlation r...

    Started by wiredalchemist‎, 10-26-2015 09:49 PM
    • Replies: 1
    • Views: 203
    10-26-2015, 09:53 PM Go to last post
  16. Smile Need statistician

    Hi Gastrodoc from NY here. I work in a university hospital and have been working on epidemiological research. I am trying to find a statistician well...

    Started by gastrodoc‎, 10-25-2015 11:42 PM
    • Replies: 0
    • Views: 253
    10-25-2015, 11:42 PM Go to last post
  17. imultivariate analysis?

    Hi, I have some data looking at a few variables and whether they are different for patients receiving/not receiving certain treatment. They are a...

    Started by klara.m‎, 10-24-2015 09:13 AM
    • Replies: 3
    • Views: 268
    10-24-2015, 04:09 PM Go to last post
  18. Comparing data between >2 groups, not sure if continous

    hello everyone. I have a problem in deciding which test to solve this situation: I have 7 groups of patients, and I want to test wheter the...

    Started by TeoTeo‎, 10-23-2015 11:14 AM
    • Replies: 0
    • Views: 167
    10-23-2015, 11:14 AM Go to last post
  19. Cox regression with age as time scale and the proportional hazards assumption

    Hello. I am currently working on a Cox regression in SPSS (Complex Samples). The cox analysis has age as time scale and calendar year as...

    Started by rcordtz‎, 10-20-2015 03:56 PM
    assumption, cox proportional hazard, log-log plot, time scale
    • Replies: 0
    • Views: 228
    10-20-2015, 03:56 PM Go to last post
  20. Survival Analysis - how to deal with replicates

    Hi, I hope someone will be able to help me with my problem, which probably is plain simple. :confused: I work on immunity experiment with fruit...

    Started by Buckyball‎, 10-19-2015 09:42 AM
    • Replies: 5
    • Views: 279
    10-19-2015, 02:42 PM Go to last post
  21. Survival analysis

    I know this forum is probably not the right place to post my question, but considering the impressive help I have obtained hare and the (unimpressive...

    Started by Bio_Stat‎, 10-16-2015 02:48 PM
    • Replies: 3
    • Views: 245
    10-19-2015, 07:53 AM Go to last post
  22. Need help with Poisson Distribution

    Hi Everyone! I`ve been really stuck on a biostats question that just doesn`t seem to make sense. The work I have is Pr(X) = (e^-u) (u^x) / X!...

    Started by Opendome‎, 10-17-2015 05:40 PM
    • Replies: 4
    • Views: 347
    10-18-2015, 05:33 PM Go to last post
  23. sample size calculation non-inferiority trial

    Dear Sir I need your help with a sample size calculation. We are planning to do a phase 3 non-inferiority randomised study comparing chemotherapy...

    Started by venkat‎, 10-15-2015 02:56 AM
    • Replies: 4
    • Views: 328
    10-17-2015, 03:14 AM Go to last post
  24. censoring provide one example

    Hi there, Censored variables come up usually in survival analysis (also in reliability) where the time to event is censored. Thus, usually (or I...

    Started by leo nidas‎, 07-06-2010 12:34 PM
    • Replies: 8
    • Views: 3,243
    10-17-2015, 01:08 AM Go to last post
  25. 2 roc curves (from a study with 2 biomarkers) in one curve

    Hy, I have a problem about solving something in R. It's about 2 roc curves of a 2 biomarkers... and I have to plot it in one curve and calculate the...

    Started by raluca‎, 10-16-2015 09:59 AM
    roc curves
    • Replies: 3
    • Views: 205
    10-16-2015, 01:45 PM Go to last post
  26. Paired analysis/ Stuart-Maxwell test

    Hi everyone, I am performing a paired analysis, cases paired with controls, with each individual having a status of current,former or never. I...

    Started by yourela3‎, 10-15-2015 10:36 AM
    • Replies: 0
    • Views: 175
    10-15-2015, 10:36 AM Go to last post
  27. Determine Sample Size from Power for Two Sample Proportions

    Hello Everyone! I just changed to a more clinical-trials related biostatistics job and my boss, who has a clinical background, made a power...

    Started by daszlosek‎, 10-13-2015 08:28 AM
    • Replies: 0
    • Views: 201
    10-13-2015, 08:28 AM Go to last post
  28. Patterns in DNA, seperating signal from noise -- outliers?

    Hello all, I'm looking at patterns in fragments of RNA. What I need to do is separate the signals from noise in Exons (small regions of DNA/RNA)....

    Started by James1984‎, 10-10-2015 06:30 PM
    • Replies: 0
    • Views: 213
    10-10-2015, 06:30 PM Go to last post
  29. RDA in Canoco; linear dependence between variables

    Hi, I would be most grateful for help regarding the question that I was asked by the journal editor. I have reviewed several papers and this forum...

    Started by Andrzej‎, 10-09-2015 03:02 AM
    • Replies: 2
    • Views: 223
    10-09-2015, 10:35 AM Go to last post
  30. accounting for left-truncation is STATA

    Hi, I have yet another question about survival analysis, this time regarding the appropriate code using STATA. I am trying to account for...

    Started by Basia.‎, 10-09-2015 09:49 AM
    • Replies: 0
    • Views: 129
    10-09-2015, 09:49 AM Go to last post
  31. survival analysis - concerns about duration times

    Hello, I'm very much a beginner at survival analysis - i know the basics, but I still get a bit lost when it comes to details. I am researching...

    Started by Basia.‎, 10-08-2015 07:03 AM
    duration, survival analysis
    • Replies: 1
    • Views: 189
    10-08-2015, 07:39 AM Go to last post
  32. Sample size calculation for Chi square Test

    Hi, I have trouble determining the sample size for a simple Chi Square Test. My problem is the following: I tried to calculate the sample size for...

    Started by ehi895‎, 08-30-2015 09:03 AM
    • Replies: 2
    • Views: 554
    10-02-2015, 09:36 AM Go to last post
  33. Autoregresive (AR) models and stationarity - Contradiction?

    Hello, I have a problem regarding the general understanding of autoregressive (AR) models (and related models, such as MA and AR(I)MA models)...

    Started by mmercker‎, 10-01-2015 02:15 PM
    ar model, arma, autoregressive, moving average process, time series
    • Replies: 0
    • Views: 238
    10-01-2015, 02:15 PM Go to last post
  34. Clinical research, Adequate statistical approach?

    Dear all! Having completed basic science projects, entering clinical research demands a whole set of other statistical approaches. Please help :-)...

    Started by DrDan‎, 09-28-2015 05:40 PM
    • Replies: 5
    • Views: 427
    09-28-2015, 10:38 PM Go to last post
  35. question about incidence and prevalence

    I have a question about incidence and prevalence, so maybe it's off topic (if so can anyone recommended another forum?) I have a paper that claims...

    Started by JuanT‎, 09-22-2015 01:07 AM
    incidence, prevalence
    • Replies: 4
    • Views: 497
    09-26-2015, 10:36 PM Go to last post
  36. homogeneity of risk ratio (relative risk) across strata

    Greetings all. In a stratified analysis, the Breslow-Day test evaluates homogeneity of odds ratios across strata. Is there a comparable test for...

    Started by js62‎, 09-25-2015 06:03 PM
    • Replies: 2
    • Views: 298
    09-25-2015, 09:59 PM Go to last post
  37. Change from or adjust for baseline for Binary outcomes

    Hi, any thoughts on how to estimate change from baseline, or adjust for baseline value when both the baseline value and the post-intervention...

    Started by DSB‎, 09-24-2015 03:54 AM
    binary data; baseline
    • Replies: 2
    • Views: 303
    09-24-2015, 08:24 AM Go to last post
  38. Sampling Behavior of a count

    Undercoverage is a problem that occurs in surveys when some groups in the population are underrepresented in the sampling frame used to select the...

    Started by robertshane‎, 09-21-2015 10:09 PM
    sampling, sampling distribution
    • Replies: 1
    • Views: 277
    09-21-2015, 10:22 PM Go to last post
  39. survival analysis - setting up data for Stata stset

    Hello, I've the following dataset: where: date0 and date1 are initial and final period phase=1 indicates expansion and phase=-1 contraction...

    Started by fralibero‎, 09-21-2015 09:47 AM
    • Replies: 0
    • Views: 175
    09-21-2015, 09:47 AM Go to last post
  40. Unhappy correlation between estimation of gestational age during pregnancy by diffl methods

    what statistical test should be used for finding correlation between gestational age estimated from clinical method and that from ultrasound during...

    Started by doel‎, 09-20-2015 03:26 AM
    • Replies: 6
    • Views: 442
    09-21-2015, 08:54 AM Go to last post
  41. a series of T tests more appropriate than ANOVA here?

    Hi all, I'm writing up some experimental results, which I believe I know how to analyze, but wanted to get some frank and impartial feedback before...

    Started by BWGIA‎, 07-03-2011 10:18 PM
    anova, dunnett t test, t test
    • Replies: 10
    • Views: 3,269
    09-19-2015, 06:02 AM Go to last post
  42. Applying Statistical Methods to Biophysical Chemistry Research, IDP Ensembles

    Hello! I am a second-year chemistry graduate student studying intrinsically disordered proteins (IDPs). IDPs do not adopt a stable folded state at...

    Started by katherynpenrod‎, 09-15-2015 01:39 AM
    biophysical, chemistry, help needed, methods, proteins
    • Replies: 0
    • Views: 315
    09-15-2015, 01:39 AM Go to last post
  43. How many B-type colonies should I test?

    Here is a current problem from my research project I could use some help with. Of four colonies from genetic background A, two have phenotype X. ...

    Started by rcorrea21‎, 09-14-2015 08:45 PM
    • Replies: 0
    • Views: 219
    09-14-2015, 08:45 PM Go to last post
  44. comparison of two tests with gold standard . which statistic analysis to be used ?

    Hi . I have just finished a study where in two tests were performed on the same patients and final diagnosis checked with the gold standard performed...

    Started by havana‎, 09-12-2015 08:32 AM
    • Replies: 1
    • Views: 286
    09-12-2015, 01:19 PM Go to last post
  45. Odds ratio and p-value

    could anyone plz help me out.... PRESCENCE OF INURY TO OCULAR ADNEXAE YES NO MILD 70 12 MODERATE ...

    Started by jacob‎, 09-04-2015 12:05 PM
    • Replies: 10
    • Views: 621
    09-04-2015, 09:48 PM Go to last post
  46. Test for linear trend in odds ratio in linear regression

    I often see epidemiological studies where a continuous variable has been divided into quantiles and the odds ratios for each quantile compared with a...

    Started by Disvengeance‎, 07-13-2014 10:50 AM
    • Replies: 10
    • Views: 2,318
    09-04-2015, 02:16 PM Go to last post
  47. Age-adjusting survey data to compare weighted estimates from multiple surveys?

    Hello, I am looking to compare weighted estimates (counts and proportions) of people with disabilities from the National Health Interview Survey,...

    Started by GrumpyEpiGuy‎, 09-03-2015 02:36 PM
    • Replies: 0
    • Views: 277
    09-03-2015, 02:36 PM Go to last post
  48. Multivariate Analysis for a paired subject longitudinal microbiome study

    I am trying to finish my stats analyses for a microbiome study, and the last thing on my list is multivariate analysis. I have a paired group of...

    Started by Gilthoniel‎, 09-03-2015 10:55 AM
    longitudinal study, microbiome, multivariate analysis, paired sample
    • Replies: 0
    • Views: 214
    09-03-2015, 10:55 AM Go to last post
  49. analysis for sparse contingency table

    I am analyzing a 2x2x3x2 contingency table. The covariates are treatment (2 different kinds, TR1 and TR2, both binary), location of treatment (3...

    Started by jpluta26‎, 08-31-2015 02:58 PM
    categorical data analysis, contingency table, log-linear, sparse
    • Replies: 2
    • Views: 432
    08-31-2015, 10:12 PM Go to last post
  50. Risk Ratio and Confidence Intervals...

    Hello, I would be hugely grateful if someone could help shed some light?! As I understand it, Risk Ratio (RR) of <1 indicates under prediction, 1...

    Started by datacrunch‎, 08-19-2015 02:31 PM
    • Replies: 8
    • Views: 663
    08-28-2015, 06:15 AM Go to last post
  51. [R]: Mixed model for non-normal y with many 0s and some high values in nested design

    Dear all, I am currently writing my master thesis on the effect of a certain insecticide on bumble bee colonies. In particular I am testing...

    Started by master student‎, 08-05-2015 05:32 AM
    anova, mixed model, nesting, zero inflated, zeros
    • Replies: 9
    • Views: 869
    08-28-2015, 05:45 AM Go to last post
  52. repeated measure with some people quit in mid-way

    Got answered from a SPSS forum.

    Started by fengyuwuzu‎, 08-27-2015 04:24 PM
    • Replies: 1
    • Views: 267
    08-27-2015, 05:07 PM Go to last post
  53. How should I connect alleles?

    I am new at statistics and I have problem that I have no idea how to solve. I have biological data, which includes expression levels (130...

    Started by ASzy‎, 08-27-2015 11:23 AM
    alleles, biostatistics, small data set
    • Replies: 2
    • Views: 219
    08-27-2015, 01:36 PM Go to last post
  54. Basic Sample Size Question

    hello this is my first thread, i want to ask something, example: i want to to know the association between cholesterol level (categorized as extreme...

    Started by Denxe‎, 08-27-2015 10:02 AM
    • Replies: 3
    • Views: 275
    08-27-2015, 10:23 AM Go to last post
  55. Frequent ED attenders - statistical test

    Hi I've a problem at work and looking for some suggestions as to how to progress. We took a sample of 100 patients. For each patient we...

    Started by scotchpie‎, 08-26-2015 06:16 AM
    • Replies: 11
    • Views: 497
    08-27-2015, 09:30 AM Go to last post
  56. imputations

    Dear all: I am working with data from a large cohort study in which participants were asked, retrospectively, about their work history. Data are...

    Started by sonia zam‎, 08-23-2015 05:59 PM
    • Replies: 0
    • Views: 288
    08-23-2015, 05:59 PM Go to last post
  57. Is a two-way anova enough?

    Hello everyone. As I am far away from being an expert in biostatistics and get confused by it easily (I will do some training in the next year and...

    Started by Makenshi‎, 08-19-2015 07:24 AM
    • Replies: 0
    • Views: 233
    08-19-2015, 07:24 AM Go to last post
  58. Is independent t-test still justified?

    Hello! I am kinda stuck and undecided whether I can use the independent samples t-test in a specific case I'm about to describe, so I'm hoping for...

    Started by stabilos‎, 08-18-2015 05:43 AM
    • Replies: 3
    • Views: 318
    08-18-2015, 08:14 AM Go to last post
  59. Categorical predictor

    Hi all I have one question concerning the presentation of results from a regression model. If you have a predictor with more than 2 categories...

    Started by sternchen‎, 08-11-2015 01:59 PM
    • Replies: 3
    • Views: 452
    08-16-2015, 11:16 AM Go to last post
  60. Case Based Learning

    Hi - I teach a case-based class in Biostatistics at a small liberal arts college and am looking for good (or bad!) examples of primary literature...

    Started by BiostatsProf‎, 08-14-2015 04:31 PM
    • Replies: 0
    • Views: 208
    08-14-2015, 04:31 PM Go to last post

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