# medical statistics

1. ### Looking desperately for advice regarding the statistically correct analysis of dependent data in medical research

Hello, my name is Andy and I am racking my brain with the following research question: Let's assume you are a surgeon who wants to remove a tumor which is exactly in the middle of the abdomen. The tumor is surgically accessible from a left flank approach or right flank approach in general...
2. ### Kruskal-Wallis, Dunn's Test, Multiple Mann-Whitney-U Test

Hello everyone, I am studying immue cell distribution in different types of nontomourous (n=66), precancerous (n=67) and malignant tissues (n=48) in a single patient cohort. As you can see in the violin plot attached below, I started out by applying the K-W test to compare the distribution in...
3. ### Which statistical tests are appropriate for estimating drug treatment effects in a crossover design (transition from medication to placebo)?

Hi all! I am interested in estimating drug treatment effects in a crossover design where I have a baseline, week 20 and week 40 measurements (1. univariate; 2. multivariate) for a set of 30 patients. 15 of these patients were treated with active medication during the first phase (baseline to...
4. ### tests of agreement between diagnostic tests

I need to assess agreement between to variables. The problem is that one of the variable is a continuous variable and the other is a categorical variable. I create a test that gives a certain value to a the compression of the brain. The gold standard test gives a categorical value among...
5. ### Can I combine univariate and multivariate HR?

Hi guys. I'm doing a meta-analysis of survival based on a blood marker, and not all the studies have provided a multivariate hazard ratio. Some have given a univariate hazard ratio (usually where it is not significant) and I would like to put them into the random effects analysis also. Should I...
6. ### Confidence interval: true or false?

We have measured the concentration cesium-137 in the tissue of 15 tunafish. We may consider the distribution as normal distribution and a 95 % Confidence Interval for the mean concentration was calculated to (5.03 to 6.71) (Bq/kg). Is the following statement true or false: "The interval means...

As part of my final year Bsc degree I am writing a research proposal. HOWEVER I am struggling to wrap my head round which statistical test would best suit my data. The Research is an RCT with an intervention and a control group (2 groups). I would like to compare the incidence rate of...
8. ### How do you use “dput” to upload to stackoverflow?

I'm a complete nube, never programmed in my life and downloaded R two days ago. Trying to upload a data table in R to stackoverflow for help with data analysis. Recommended to use "dput" could someone explain in easy to understand terms how to do so.
9. ### Medical Audit New Column based off three other columns

Hello I'm Sean a final year medical student doing an audit on some ultrasound data. I'm new to programming and R. What I want to do is create a column of data based off the values in three other columns. I have attached a picture to refer to because its a bit difficult to describe So I...
10. ### Statistical Analysis for Heart Monitors

Hi everyone, I am an English person who's never taken statistics (yikes, right?). Well, now I'm working a job where I need some ideas of what kinds of statistical analysis might be used to make sure that medical devices (heart monitors in this case) are working properly. I'm writing a...
11. ### PAF through formula or through Conditional Logistic Regression

Hi all, In a large registry dataset of psychiatric patients, if one wants to find the excess risk of schizophrenia patients developing depression, what would be the best method to apply: 1) Use the relevant formula to calculate PAF (Population Attributable Fraction). Formula can be...
12. ### Repeated measures ANOVA; missing data and multiple measures at each time point

Hi TalkStats I have data from a project. The data is the blood pressure for each participant at day of "baseline" visit, and 3 time points after baseline visit. Index these baseline and post-baseline time points j=0,1,2,3. For the ith participant, at time point j, we have measurement...
13. ### non-parametric data for reference ranges

Hello, I am very new to statistical analysis, but am very excited to to be learning it. I am working on finding reference ranges for some mammalian blood work. I hope this is the appropriate place to post my query, otherwise, my apologies. I have successfully found my reference ranges...
14. ### Multiple value Chi Squared test in SPSS

Hello, I am currently doing a study into factors that affect mortality in a particular type of bacterial infection. I would like to compare certain patient characteristics. One of which is the specialty that the patient is under. I currently have a variable in SPSS that has three values...