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    Interim and final analysis in clinical trials

    Hello, I would like to know the opinion of biostatisticians with experience in clinical studies with adaptive design. I participate in a clinical trial with adaptive design as a main biostatistician. The trial is double blinded placebo-controlled study. My responsibility is to provide final...
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    Strange results of logistic regression

    Hi everyone, I have strange results of logistic regression: The model is following: dependent: success of treatment, 0 - No, 1 - Yes, possible predictors: treatment, 1 or 2 (numeric) and sex with 2 different codes, first: (F=0, M=1), second: (F=1, M=0). If I build regression with treatment...
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    Multiplicity adjustment in correlation analysis

    Hi everyone, I would like to know the opinion of experienced statisticians. If I perform a correlation analysis: calculation of 20 correlation coefficients: one variable with 20 other variables, should I correct for the multiplicity? If such an adjustment is needed, then which method is most...
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    How to assess variance for sample size calculation

    Hi everyone, I am going to calculate sample size for a clinical trial. I need to compare two groups by quantitative variable. I have data of a previous phase trial: Ns, means and SDs for each group. What would be better way to assess variance for using formula for sample size: to take biggest...
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    Time series analysis. Autocorrelation and differences

    I try to analyze the Wolf numbers. I have never analyzed time series before. Firsty I calculate autocorrelation coefficients. Biggest coefficients were for delays: 1, 2, 6, 7, 8, 9, 10. I calculated differences D(-1), D(-9). But for both calculated time series autocorrealtion coefficients for...