In epidemiologic studies and disease prevention trials, interest often involves estimation of the relationship between some disease endpoints and individual exposure. In some studies, due to the ...

Cheung and colleagues warned that underpowered studies that committed a type II error will discourage clinicians from using effective treatment.1 I agreed with this ...

Back in the day, we learned in statistics that you need a sample size of at least 2% of the size of population to make statistically significant conclusions about the behavior of the population. In ...

calculate confidence intervals for the mean using the t or z distributions (depending upon the sample size) complete formal hypothesis tests about whether a sample mean is different from a specific ...