A scientist is conducting a study on the effect of eating chocolate and overall mood. They believe that gender is a significant factor.The participants are divided by gender.Then, within each group, participants are randomly assigned to consume either chocolate or a placebo and then rate their mood for the day. This experiment will run for two weeks.

Which type of experimental design does this situation describe?

• Case-Control Design
• Completely Randomized Design
• Matched-Pair Design
• Randomized Block Design