I scanned my answers for you that i did at the start of the year ( i did SOC 1st)
Here you go
http://i48.tinypic.com/1256pug.jpgFor some reason i couldn't get the other side to scan but the answers are basically
q2. 1 cycle of NREM (1 2 3 4 3 2 1 ) = 70- 90 mins
1 progression of NREM stages 1-4 ( 1 2 3 4 ) = 45-60 mins
20 % rem 80% non rem in a nights sleep
1 complete cycle of sleep inc REM = 80-120 mins
q3. once delta waves appear- this marks the beginning of slow wave sleep. because in stage 3 a pattern of low freq delta waves indicates a stage of deep sleep inc. slow waves; hence 'slow wave sleep'. low freq=slow waves. sws serves as a transition between stages 3 + 4 of NREM sleep.
(that question was answered really badly by me...whoops!)
q4. because internally the brain and body are active, while externally, the body appears calm and inactive.
Hope that helps...jesus i should really be focusing on my homework and not someone elses.