Medical: REM Sleep REM (rapid eye movement) sleep is sleep during which most dreams occur. Each night a person has both REM and non-REM sleep. However, it is thought that children have more REM sleep than adults (Reference: Secrets of Sleep by Dr. A. Borbely).

Assume that REM sleep time is normally distributed for both children and adults. A random sample of n1 510 children (9 years old) showed that they had an average REM sleep time of x1 5 2.8 hours per night. From previous studies, it is known that s 5 0.5 hour. Another random sample of n2 510 adults showed that they had an average REM sleep time of x2 5 2.1 hours per night.

Previous studies show that s2 5 0.7 hour. Do these data indicate that, on average, children tend to have more REM sleep than adults? Use a 1% level of significance.

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