Dr. Brown wanted to study the effect of music on memory. She designed an experiment with three conditions: no music, happy music, and sad music. In each condition, participants would learn the same list of words with or without listening to music, and their memory of the words would be tested afterwards. Dr. Brown recruited 30 participants, 10 of whom signed up for the experiment in the morning, 10 in the afternoon, and 10 in the evening. Dr. Brown decided to let the morning group study the words without music, the afternoon group with happy music, and the evening group with sad music---
What are the independent variable and dependent variable in this experiment?