Determine whether the study is an observational study or an experiment.

Explain.

(a) Researchers conduct a study to determine whether cataract surgery patients experience different comfort levels during their first and second surgeries.

Researchers based their results on a verbal questionnaire.

(b) In a study about smoking and vaping cues, researchers randomly assign 936 current or former smokers or vapers to watch a video that involves smoking, vaping, or neither. The subjects are then asked to report their level of desire to smoke or vape.