Recent content by lotw

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    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...
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    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...
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    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 =...
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    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...
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    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)...
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    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...