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. Author manuscript; available in PMC: 2013 Jun 12.
Published in final edited form as: J Sleep Res. 2001 Sep;10(3):181–192. doi: 10.1046/j.1365-2869.2001.00256.x

Figure 4.

Figure 4

Average Stanford sleepiness scale ratings (mean ± SEM) from bedtime questionnaires, wake time questionnaires, and test bouts during the night shifts. 1 = ‘feeling active and vital; alert; wide awake’ and 7 = ‘almost in reverie; sleep onset soon; must struggle to remain awake.’ (●) The melatonin session, (○) the placebo session. B = Bed-time ratings; W = Wake time ratings; numbers 1–4 indicate the sequential test bouts during the night shifts. *P < 0.01.