Question

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†. Assume that REM sleep time is normally distributed for both children and adults. A random sample of n₁ = 8 children (9 years old) showed that they had an average REM sleep time of x₁ = 2.9 hours per night. From previous studies, it is known that σ₁ = 0.6 hour. Another random sample of n₂ = 8 adults showed that they had an average REM sleep time of x₂ = 2.40 hours per night. Previous studies show that σ₂ = 0.8 hour. Do these data indicate that, on average, children tend to have more REM sleep than adults? Use a 10% level of significance. Solve the problem using both the traditional method and the P-value method. (Test the difference μ₁ − μ₂. Round the test statistic and critical value to two decimal places. Round the P-value to four decimal places.)

test statistic	?
critical value	?
P-value ?

Answer 1