Acoin-operated machine sells plastic rings. it contains 6 yellow rings, 11 blue rings, 15 green rings, and 3 black rings. sarah puts a coin into the machine. find the theoretical probability she gets a black ring. express your answer as a decimal. if necessary, round your answer to the nearest thousandth. a. 11.667 b. 0.171 c. 5.833 d. 0.086

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.