In a 2017 study design to investigate the effects of exercise on second-language learning, 40 subjects were randomly assigned to one of 2 conditions: an experimental group that engaged in simultaneous physical activity while learning the vocabulary in a second language and a control group that learned the vocabulary in a static learning environment. Researchers found that learning second-language vocabulary while engaged in physical activity led to higher performance than learning in a static environment.
1. What features of a well-designed experiment are missing from this study? Select all that apply
Random assignment
Two-group division