Use the Following Information for Questions

Multiple Choice

Use the following information for questions:
A student doing an internship at a large research firm collected the following data, representing all of the studies the firm had conducted over the past 3 years.
-Define the events E = {the study was an experiment}, U = {the study used randomization} and R = {the study was a retrospective observational study}. Which of the following sets of events are disjoint?

A) E and U
B) E and R
C) U and R
D) All three
E) None of the above