Atrack coach is trying to improve the  50-meter-dash times of the track team. he times each student and then implements a month-long training program. at the end of the program, he timed each of the students again. the box plots show the number of seconds it took the students to run the  5050-meter-dash before and after the program. using the plots, how much did the median change?


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.