REM sleep is the phase of sleep when most active dreaming occurs. In a study, the amount of REM sleep during the first four hours of sleep was described by a random variable T with probability density function fstd 1 1600 t if 0 < t < 40 1 20 2 1 1600 t if 40 , t < 80 0 otherwise where t is measured in minutes. (a) What is the probability that the amount of REM sleep is between 30 and 60 minutes? (b) Find the mean amount of REM sleep.

Unit 1 Review 1) inferior people who could be exploited. 2) Gold, Natural resources, land, wealth 3) dispute over the denominations of Catholicism and the Church of England 4) British sent many ships to America to establish colonies. Also many British came to the new world for religious reasons. The Pilgrims and Puritans were the more prominent immigrants. 5) just looking for...