A nurse measured the blood pressure of each person who visited her clinic. Following is a relative-frequency histogram for the systolic blood pressure readings for those people aged between 25 and 40 years. The blood pressure readings (in mm Hg) were given to the nearest whole number. What class width was used to construct the relative frequency distribution?
Systolic Blood Pressure for People Aged 25-40 Years
Click the icon to view the histogram for systolic blood pressure.
O A. 100 mm Hg
OB. 9 mm Hg
O C. 10 mm Hg
OD. 11 mm Hg

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.