Researchers conducted an experiment to test the effects of a meditation training on stress during public speaking. They recruited 50 participants. The participants were split into 2 groups; the Meditation Group received a 10-minute guided meditation, while the Control Group sat quietly in a room for 10 minutes. Then, every participant had to deliver a pre-written speech to a group of 20 strangers. Afterwards, the researchers measured each participant's stress using a validated self-report measure.

what is the independent variable in this study? what is the dependent variable? and is this a between-subjects design or within-subjects design? . If between-subjects, is it a pretest-posttest design or a posttest-only design?