in my prospective cohort study I will assess the serum level of a vitamin in a group of patients
the normal reference serum range is 10-30 in normal population
there is no control group
then i will correlate the serum level with later occurrence of outcome (yes or no)
So I need to know what is the extra information you need for sample size calculation
the normal reference serum range is 10-30 in normal population
there is no control group
then i will correlate the serum level with later occurrence of outcome (yes or no)
So I need to know what is the extra information you need for sample size calculation