a carpenter has a bag with 15 nails there are 4 brass nails, 9 nickel nails, and 2 copper nails he takes out three nails, one at a time, without replacement what is the probability that the first nail is brass, the second is nickel, and the third is copper

Arandomized controlled trial is designed to evaluate the effect of metoprolol in patients with heart failure. while preparing for statistical analysis, the researcher reviews some common types of statistical errors. which of the following statements is true regarding a type i error in a clinical study? a. the study is not significantly powered to detect a true difference between study groups. bthe null hypothesis is true but is rejected in error. c. the null hypothesis is false but is accepted in error. d. type i error is also known as beta and is usually 0.1 or 0.2. e. type i error depends on the study's confidence interval.