A researcher wanted to investigate whether playing an immersive virtual reality (VR) video game for a prolonged period affects a person's reaction time.
To do this, the researcher measured the reaction times of 12 volunteer students.
Each student then played a fast-paced VR video game for two hours.
Immediately after playing, the researcher measured their reaction times again under the same environmental conditions.
Give three ways that the researcher could improve this investigation to obtain more valid and reliable results.
