1. 10-14-2010
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Forum: Biostatistics

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

  1. ANOSIM: significant p-value and small R-value. How?

    I am analyzing data of a large sample size ('000's of samples) via one-way ANOSIM. Results appear contradictory: Highly significant p-value...

    Started by dt87‎, Yesterday 11:22 PM
    • Replies: 2
    • Views: 40
    Today, 01:17 AM Go to last post
  2. Repeated measures or two-way ANOVA ? + sample size estimation

    A sample of patients will undergo two treatments. Each patient will receive both treatments.One treatment will on the left side and the other...

    Started by Logician‎, Yesterday 07:40 AM
    • Replies: 3
    • Views: 96
    Yesterday, 04:40 PM Go to last post
  3. case control study

    i want to do a study i have with me serum cholesterol levels of patients with intracerebral hemorhage and infarcts other studies some say low...

    Started by valsa‎, Yesterday 02:07 AM
    • Replies: 1
    • Views: 73
    Yesterday, 09:03 AM Go to last post
  4. Unhappy A dumb question about univariate analysis (repost from applied statistics)

    Hello I'm quite dumb regarding statistics, but i really am looking for a simple answer to a simple question. the question is: how do i explore data...

    Started by Kimboz‎, 12-19-2014 04:05 AM
    • Replies: 2
    • Views: 141
    12-19-2014, 05:54 AM Go to last post
  5. Two-proportion z test: is it best for my problem, and can I pool data?

    I am examining populations (cultures) of yeast cells and scoring them for a particular trait. The data is categorical; within a population, a yeast...

    Started by dmcameron‎, 12-18-2014 04:24 PM
    pooling data, proportion test, z-test
    • Replies: 0
    • Views: 136
    12-18-2014, 04:24 PM Go to last post
  6. Repeated-measure ANCOVA

    Hi there, I'm looking at a study which is measuring the effect of medication A on aggressive behaviour over time, after they have failed...

    Started by cheoksoon‎, 12-16-2014 05:20 AM
    • Replies: 0
    • Views: 108
    12-16-2014, 05:20 AM Go to last post
  7. Any statisticians out here please? £50 voucher offer

    I am doing a survey as part of my MSc project and need someone to review the protocol from a stats point of view, including helping to determine the...

    Started by brownbabygirl‎, 08-11-2014 04:13 PM
    2 Pages
    1 2
    • Replies: 23
    • Views: 1,584
    12-15-2014, 06:28 PM Go to last post
  8. Salmon gender

    During the salmon run we have a daily count of fish, males and females. I want to determine if there is an equal probability each day of getting an...

    Started by KellyD‎, 12-11-2014 06:16 PM
    • Replies: 6
    • Views: 238
    12-13-2014, 05:46 AM Go to last post
  9. clinical trial interpretation

    Hi! given two randomised clinical trials, the first compare treatment A vs B; the second compare treatment A vs B vs C. after enrolment, the...

    Started by stator‎, 12-12-2014 02:32 PM
    clinical trial
    • Replies: 5
    • Views: 161
    12-12-2014, 07:57 PM Go to last post
  10. Preparing for Meta Analysis

    Hello Everybody, I am a physician and a researcher, have been studying the meta-analysis subject for a while now, and we are in the process to...

    Started by messadua‎, 11-15-2014 07:30 AM
    database, diagnostic test, meta analysis, predictors, structure
    • Replies: 1
    • Views: 246
    12-12-2014, 05:12 PM Go to last post
  11. Compare 2 tests - Bland Altman vs. area under curve

    Hello, I want to compare the performance of 2 binary classification tests (positive vs. negative diagnosis) from the same sample (n=430). I have...

    Started by finnakerstrom‎, 12-09-2014 04:15 PM
    bland-altman, roc curves
    • Replies: 6
    • Views: 221
    12-10-2014, 01:54 AM Go to last post
  12. Smile Where Do I Start?

    I need assistance with the following problem: In 1960, census results indicated that the age at which American men first married had a mean of...

    Started by sditizio‎, 12-09-2014 12:12 AM
    • Replies: 3
    • Views: 199
    12-09-2014, 08:00 AM Go to last post
  13. Normality assumption for ARIMA analysis

    I have two time series that I wish to quantify their relationship using arima analysis. Both data series are not normally distributed, even after...

    Started by SandraC‎, 12-07-2014 06:13 AM
    • Replies: 0
    • Views: 166
    12-07-2014, 06:13 AM Go to last post
  14. Help needed, linear regression SPSS for birthweight controlling for maternal age

    Hello all, I am in need of help. I am performing a study looking at the effects of Assisted Reproductive Technology on birthweight, and I would...

    Started by ironslave‎, 12-05-2014 11:07 AM
    • Replies: 0
    • Views: 154
    12-05-2014, 11:07 AM Go to last post
  15. Power Calculation

    I will admit that I have not sat around racking my brain on this one, but thought it may be nice to get some input. I was enlisted to help out...

    Started by hlsmith‎, 03-11-2014 11:46 AM
    • Replies: 4
    • Views: 442
    12-05-2014, 04:17 AM Go to last post
  16. Follow-up tests with 2-way within-subject repeated measures ANOVA

    Hi everybody, I've been doing a 2-way within-subject repeated measures ANOVA and I have some questions: 1) Is it correct that I'm only...

    Started by Eric2014‎, 12-04-2014 12:19 PM
    anova, follow-up, t-test
    • Replies: 0
    • Views: 164
    12-04-2014, 12:19 PM Go to last post
  17. data exploration continue dependent variable or categorical dependent variable ?

    Hello everyone if you are give a data set with age ask outcome(dependent variable) but in the data set age has two scale categorical and...

    Started by dockiss‎, 12-04-2014 05:32 AM
    • Replies: 0
    • Views: 123
    12-04-2014, 05:32 AM Go to last post
  18. How can I obtain contrast statment for linear trend test ?

    Hi, I hope someone can explain this to me. I have obtained the following from the SAS website, but I cannot apply it to my data where I have 11 dose...

    Started by Bracknell‎, 11-27-2014 06:18 AM
    • Replies: 3
    • Views: 294
    12-02-2014, 09:18 AM Go to last post
  19. Should I use a two sample or paired t.test?

    Hello, I´ve just wanted to post one simple question. I am comparing the removed area through endonasal approach in left or right side. It means,...

    Started by emilio.gonzalez.martinez‎, 11-23-2014 05:44 PM
    comparing, paired test
    • Replies: 5
    • Views: 436
    11-28-2014, 07:40 AM Go to last post
  20. Cox-analysis: right approach in this case?

    Hello all, I would be interested in your thoughts about whether this approach sounds correct to you or not. I have data of a cohort of subjects...

    Started by Ralph84‎, 11-28-2014 06:19 AM
    • Replies: 0
    • Views: 137
    11-28-2014, 06:19 AM Go to last post
  21. Paired t test or two sample ANOVA

    Hi, The experiment is investigating whether IQ changes based on certain training (there are 2 courses and a control - nothing). I have the IQ of...

    Started by roosterrocky‎, 11-26-2014 07:19 PM
    • Replies: 2
    • Views: 224
    11-27-2014, 01:03 PM Go to last post
  22. Which tests and steps to do?

    Hey there! I am new to this so I would really really appreciate any help! I haven't got statistical education but still I have to use it, so I want...

    Started by Veronikite‎, 11-27-2014 04:49 AM
    • Replies: 0
    • Views: 137
    11-27-2014, 04:49 AM Go to last post
  23. Where can I access the actual DATA used from medical studies?

    Hello, I have a project in my regression class where I need to find 2 studies that used regression analysis, and I need to reproduce their...

    Started by BearJewJ‎, 11-16-2014 12:59 PM
    • Replies: 3
    • Views: 337
    11-18-2014, 10:53 AM Go to last post
  24. Test to look at increasing admission incidence in a population

    We are trying to establish if a significantly higher proportion of obstetric patients in our hospital are being admitted to intensive care than...

    Started by RikThomas‎, 11-14-2014 03:10 PM
    • Replies: 0
    • Views: 180
    11-14-2014, 03:10 PM Go to last post
  25. Study design issue: using national survey data as control group

    I'm working on a descriptive study of children who have specific health issues. Unfortunately, there is no good internal comparison group, so I'd...

    Started by adamsaa23‎, 10-31-2014 12:13 PM
    • Replies: 3
    • Views: 306
    11-13-2014, 11:07 PM Go to last post
  26. Confounder analysis for LOGISTIC regression

    Hi there, I have the following situation: I have a logistic regression analysis, in which I have 3 variables: The dependent variable- dichotomous-...

    Started by yohayohay‎, 11-09-2014 05:30 AM
    confounders, continous variable, logistic regression
    • Replies: 2
    • Views: 228
    11-13-2014, 11:01 PM Go to last post
  27. biostatistics for ordinal variable

    The study is perspective. the subject is : the effect of an intervention on antibiogram level I will have a antibiogram value at (4: for...

    Started by parisaarzani‎, 11-08-2014 03:05 PM
    biostatistics, ordinal value, repeated measure
    • Replies: 11
    • Views: 484
    11-13-2014, 04:02 PM Go to last post
  28. Statistical significance in reproducibility study

    Thanks for taking the time to read this thread and help me out! I recently carried out a reproducibility study in which 15 observers from 4 groups...

    Started by reproducibilityhelp‎, 11-09-2014 05:28 PM
    • Replies: 0
    • Views: 164
    11-09-2014, 05:28 PM Go to last post
  29. Predicted vs. actual survival

    Hi guys, I am trying to do the statistics part myself for a project which looks at ability of a model to predict survival in patients. For the...

    Started by jhm3‎, 11-07-2014 06:49 PM
    • Replies: 0
    • Views: 219
    11-07-2014, 06:49 PM Go to last post
  30. Comparing blood levels at 2 time points between 2 groups

    Hey everyone, I'm incredibly inexperienced when it comes to biostatistics. For my bachelor's thesis, I need to do statistical analyses, and I want...

    Started by Scoltey‎, 11-07-2014 09:16 AM
    • Replies: 1
    • Views: 199
    11-07-2014, 09:28 AM Go to last post
  31. Age-adjusted Cumulative incidence

    Hello, Somebody knows what is the method to calculate an age-adjusted cumulative incidence for a clinical event? Also, could you tell me if...

    Started by didye‎, 11-06-2014 01:34 PM
    • Replies: 1
    • Views: 161
    11-06-2014, 04:32 PM Go to last post
  32. Is this linear mixed effect repeated measures?

    I'm looking for some clarity on the following. This experiment tested the null hypothesis that 2 methods for measuring the length of an animal...

    Started by dt87‎, 11-04-2014 09:13 PM
    • Replies: 0
    • Views: 228
    11-04-2014, 09:13 PM Go to last post
  33. summarizing health indicators by facility

    Hi! A bit of background about the current issue: We're looking at a set of 6 indicators (simple binary variables) aggregated at a facility...

    Started by jamesmartinn‎, 11-04-2014 10:19 AM
    • Replies: 0
    • Views: 139
    11-04-2014, 10:19 AM Go to last post
  34. Significance testing among groups of time series data

    I have produced 2 groups of time series data. Each group contains 100 time series, each of which is a solution to an ordinary differential equation...

    Started by ELMC‎, 11-01-2014 01:26 PM
    • Replies: 0
    • Views: 279
    11-01-2014, 01:26 PM Go to last post
  35. repeated measurements - ANOVA, friedmann's test or kruskal wallis?

    Dear all, I am a junior doctor getting involved in medical statistics, of which my knowledge is very preliminary. The problem I face is the...

    Started by vzavvos‎, 10-29-2014 05:25 PM
    friedman, repeated measurements
    • Replies: 0
    • Views: 232
    10-29-2014, 05:25 PM Go to last post
  36. Noob question

    why when modeling do some variables have significant p values yet they are not included in the model ? I was doing a cox regression model and...

    Started by Logician‎, 10-28-2014 07:58 PM
    variables in models
    • Replies: 7
    • Views: 356
    10-29-2014, 04:05 PM Go to last post
  37. Post Fisher test or interaction terms to determine if 2 groups are different

    Hi, I split my sample in 2 groups, participants with condition +M and participants without the condition -M. I calculated correlations and beta...

    Started by DataPilgrim‎, 10-23-2014 03:14 PM
    fisher test, groups, interaction terms
    • Replies: 3
    • Views: 280
    10-29-2014, 02:31 PM Go to last post
  38. Identical continouous dependant variables vs. unique independent variables?

    Hi guys, I'm having an issue re: the statistical test I should be using in research I am undertaking. Let's say I have a study population of...

    Started by Xami‎, 10-29-2014 12:49 AM
    exposure, land use regression
    • Replies: 2
    • Views: 238
    10-29-2014, 09:39 AM Go to last post
  39. T test comparison of 3 treatments

    Good evening, i´ve developed 3 models wich predict the extent of area covered by the studied group. what statistical test could be useful for...

    Started by jos19‎, 10-27-2014 11:16 PM
    no replicas
    • Replies: 1
    • Views: 298
    10-28-2014, 02:52 AM Go to last post
  40. ?Pearson ?point-biserial correlatiom coefficient for relationship between variables

    Hi, I'm new on this forum, thanks for reading my post! I'm trying to figure out if I've used the best method for determining a relationship between...

    Started by waynes‎, 10-27-2014 07:08 PM
    biostatistics, pearson correlation, point-biserial, valid
    • Replies: 0
    • Views: 171
    10-27-2014, 07:08 PM Go to last post
  41. Question 4 proportions to compare, each with separate N and 95% CI. use ANOVA or what?

    With the above info, what's the correct way to determine whether the proportions differ significantly? I thought I had a lovely formula that used...

    Started by StatsIsPain‎, 10-23-2014 08:52 PM
    • Replies: 1
    • Views: 227
    10-23-2014, 10:42 PM Go to last post
  42. Smile How to stratify an additive hazards model?

    Hi, I am trying to conduct a stratified additive hazards model (Aalen’s additive model). I am using Stata 12.1. The stata syntax for the...

    Started by martina.andersson‎, 10-20-2014 11:57 AM
    aalen's additive hazards, additive hazards, cox regression
    • Replies: 0
    • Views: 278
    10-20-2014, 11:57 AM Go to last post
  43. AMOS 7.0 Student Version

    Hi everybody, I would like to download Amos 7.0 Student version but I couldn't find it anywhere. Could anyone help me please?

    Started by maver37‎, 06-18-2014 01:54 PM
    • Replies: 1
    • Views: 513
    10-15-2014, 05:11 AM Go to last post
  44. ANOVA - floral longevity, seeking feedback on tests performed

    I have done my statistical analysis and would appreciate any feedback to say if my tests are appropriate. If not, what tests would you recommend? I...

    Started by caryophyllus‎, 10-11-2014 12:00 AM
    • Replies: 2
    • Views: 408
    10-13-2014, 06:51 PM Go to last post
  45. Type I and Type II SS for ANOVA, non-statistician

    Good Afternoon (non-statistician here), I have to automate a GLM within an Excel sheet that will be analyzing some toxicity data, resulted from...

    Started by BrainExploding‎, 10-10-2014 01:52 PM
    anova, glm, type i ss, type ii ss
    • Replies: 3
    • Views: 327
    10-10-2014, 03:29 PM Go to last post
  46. Negative Trend

    I am hypothesizing a decrease in a type of injury over the past decade. I have the number of admissions to my hospitals and the number of patients...

    Started by hlsmith‎, 10-09-2014 09:33 AM
    • Replies: 7
    • Views: 338
    10-09-2014, 02:03 PM Go to last post
  47. Post Selecting most consistent gene expression across multiple replicates

    Hi Members, I have microarray data set of genes with the expression value in 3 experiments. I would like to select the genes whose expression value...

    Started by anikng‎, 10-08-2014 01:22 AM
    • Replies: 0
    • Views: 240
    10-08-2014, 01:22 AM Go to last post
  48. Multifactor MANOVA Help

    Struggling mightily with some analyses for my thesis. I am using SAS for this analysis and trying to do MANOVA. I have some time-activity budget...

    Started by featherchaser‎, 10-07-2014 06:47 PM
    • Replies: 0
    • Views: 219
    10-07-2014, 06:47 PM Go to last post
  49. help with Kaplan-Meier curve

    I was trying to make a simple KM curve. The event is the death of cancer patients. The time is the time between diagnosis to last follow up. The...

    Started by sky_yin‎, 09-10-2014 01:33 PM
    • Replies: 1
    • Views: 326
    10-07-2014, 01:25 AM Go to last post
  50. Study review question for all you fellow biostat nerds. :)

    I'm thinking a welch's t-test is appropriate, but unsure of that? Can anyone lead me in the right direction? A geographer studying “hammock...

    Started by bionerdette‎, 10-04-2014 04:06 AM
    welch's t-test
    • Replies: 1
    • Views: 308
    10-04-2014, 06:49 AM Go to last post
  51. How to calculate correction factor from two sets of numbers

    Hi, Two sets of samples were centrifuges at two different revolutions/sec. I would like to calculate the correction factor for the values...

    Started by madsmad‎, 10-02-2014 03:05 AM
    • Replies: 0
    • Views: 221
    10-02-2014, 03:05 AM Go to last post
  52. Pathway/gene set enrichment: Testing if my target pathway is enriched

    Dear all, I was wondering whether you could help me with the following biostatistics question. I have consulted several people, who gave very...

    Started by Mattijs‎, 10-01-2014 12:16 PM
    • Replies: 0
    • Views: 359
    10-01-2014, 12:16 PM Go to last post
  53. ANOVA on paired data

    Hello all, I am trying to design an experiment, and in order to dig a sample size I need to know how the data will be analyzed. This is an...

    Started by NN_STAT‎, 09-18-2014 04:22 AM
    • Replies: 1
    • Views: 538
    09-27-2014, 10:44 AM Go to last post
  54. Hypothesis Test method Query

    What would be the appropriate statistical method to investigate whether patients who had a history of having drug “X” on a regular basis had...

    Started by GKK‎, 09-26-2014 12:19 AM
    • Replies: 5
    • Views: 554
    09-26-2014, 02:34 PM Go to last post
  55. [SPSS - BLR] Adding interaction term leads to multicollinearity

    Hello, I’m re-analysing survival data from another author Data: 2 Treatments (no controls); 4 Temperatures; Event = Death on day 12...

    Started by lisaclancy‎, 09-26-2014 04:48 AM
    • Replies: 0
    • Views: 369
    09-26-2014, 04:48 AM Go to last post
  56. Sample Size and Power Calculation- Stepped Wedged Design

    Hello, I am looking for an advice on sample size and power calculation for an intervention study. The study uses a stepped wedged design. The...

    Started by Ken Mutai‎, 09-25-2014 05:25 PM
    • Replies: 0
    • Views: 229
    09-25-2014, 05:25 PM Go to last post
  57. Parametric or Non-Parametric and why?

    I want to examine how three different treatments impact cytokine production in primary human cells (n=3) compared to an untreated control (example...

    Started by A.B‎, 09-22-2014 03:41 AM
    • Replies: 9
    • Views: 594
    09-22-2014, 02:20 PM Go to last post
  58. Longitudinal analysis

    I am reading a book on medical analysis using SAS. These questions relate to longitudinal analysis. During a signficant section of the book they use...

    Started by noetsi‎, 09-19-2014 01:52 PM
    • Replies: 8
    • Views: 512
    09-22-2014, 11:34 AM Go to last post
  59. Hierarchical Spatio-temporal modelling

    Is it possible to create a hierarchical spatio-temporal model in a case whereby the age specific population size is not available at any given time...

    Started by juma‎, 09-22-2014 08:59 AM
    • Replies: 0
    • Views: 233
    09-22-2014, 08:59 AM Go to last post
  60. Measuring variability within a system

    Does anyone know of a way to measure the amount of variability within a system to create a "metric" of variability that can then be used in a...

    Started by Austin‎, 09-21-2014 08:35 PM
    • Replies: 0
    • Views: 213
    09-21-2014, 08:35 PM Go to last post

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