Effects of Sleep Deprivation on Cognitive Performance: Experimental Design Analysis

In a study examining the effects of sleep deprivation on cognitive performance, researchers randomly assigned participants to either a sleep-deprivation group or a control group that received a full night's rest. The participants were then given a series of cognitive tasks to assess memory recall, problem-solving skills, and reaction times. Based on this scenario, answer the following questions:

1. Identify the independent and dependent variables in this study.

2. Discuss how random assignment contributes to the internal validity of the experiment.

3. Propose a potential confounding variable in this study and explain how it could impact the results.

4. Suggest a method for mitigating the impact of the identified confounding variable on the findings of the study.