A regional store manager wants to test whether increasing store hours increases profits, so they randomly select half of their locations to stay open an extra hour later in the evenings and compare profits between stores at the end of the month. They notice that stores open later saw higher profits on average. Is this an experiment or an observational study? Can they determine the extra hours caused the increase in sales? 

• A. Observational study; no
• B. Experiment; yes
• C. Observational study; yes
• D. Experiment; no

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the difference between an experiment and an observational study. An experiment involves actively manipulating variables to observe the effect, while an observational study involves observing and analyzing data without intervention.
2. Step 2: Identify the key elements of the scenario. The manager randomly selects half of the locations to stay open an extra hour later in the evenings, which is an active manipulation of store hours. This indicates that the scenario is an experiment.
3. Step 3: Consider the concept of causation. In an experiment, random assignment helps control for confounding variables, allowing researchers to infer causation if the results show a significant effect.
4. Step 4: Evaluate whether the random assignment of store hours allows the manager to determine causation. Since the manager randomly assigned the extra hours, they can reasonably conclude that the increase in profits was caused by the extended hours, assuming no other confounding factors.
5. Step 5: Conclude that this scenario is an experiment, and the manager can determine that the extra hours caused the increase in sales, based on the principles of experimental design and causation.