# Recent content by lotw

1. ### Analyse a survey?

Hi, It's the first time I want to analyze a survey but I can't get to the right methods/literature... a lot of what I find contradicts itself. I have the following data (also attached an image to illustrate). This is not the real story but just for illustration: Its a survey that was done for...
2. ### Calculate propability of certain outcome

So I have a question, these statistics lessons have been such a long time that I'm not sure how to calculate the following: Say that there is a new disease, and I have a test that is 100% reliable. I have tested 100 people, and have found that 3 people got the disease. So from now on this is...
3. ### Sample Size problem: Have done a trial/pilot, but how to proceed?

Small additional explanation in another example: Let's change it to medicins: You have a Person (=Variable School) with 3 different tests (=variable Test_Method) he/she is tested for blood sugar before taking the medicine that gives a score for every different test (= variable...
4. ### Sample Size problem: Have done a trial/pilot, but how to proceed?

I have a problem in calculating sample size. I did do a small pilot experiment, so this is some sample data with the same structure: df <- data.frame(ID = c(1,2,3,4,5,6,7,8,9), School = c("A","A","A","B","B","B","C","C","C"), Test_Method_A =...
5. ### plotting the effect of treatment on plants

Hello, I have some plant data, which contains several plant groups. Within the plant groups there are different plant sizes (devided in groups). For each plant I noted whether it was infected before and after the treatment: data = data.plant > str(data.plant) \$ Group.nr: Factor w/15...
6. ### Adjust for overdispersion in glm family = binomial (logit) model

I have an overdispersion problem in my model.. I have the following data: y= succes/fail (%) x= Var1 : Temperature data m1<-glm(cbind(succes,fail)~Var1, data=data, family = binomial(logit)) Call: glm(formula = cbind(succes, fail) ~ Var1, family = binomial(logit), data = data)...
7. ### Which model/test should I choose? (GLM..?)

Hello! I'm new to statistics but I am getting really stuck with my data so I hope someone could help me to choose the best statistical test. I have some test (dummy) data. I have data from 64 different hospitals, for 5 different countries countries, over 5 different years. In all of the...