Across • Allow • Analyses • Assigns • Cause • Cohort • Compares • Consuming • Correlation • Correlational • Describe • Direct • Does • Equal • Experiments • External • From • Have • Helps • Higher • Independent • Interference • Investigate • Key • Laboratory • Manipulates • Manipulating • Meta • Period • Point • Population • Precise • Primary • Randomized • Randomly • Reduce • Relationships • Results • Reviews • Sectional • Single • Them • There • They • Time • Trials • Types • Variables • When • Yield