Effects of Sleep on Memory Retention

In a recent study, researchers investigated the impact of sleep on memory retention. They divided 100 participants into two groups: one group (Group A) received a full night's sleep before completing a memory test, while the other group (Group B) stayed awake for the entire night. The researchers then measured the participants' performance on the memory test using the number of words recalled.

Based on the results of the study, which indicated that Group A performed significantly better than Group B, describe what conclusions can be drawn from this experiment. Additionally, explain one potential confounding variable that could have influenced the results.