Figure 4

Distribution of wake-up times. The percentiles with a reported wake-up times (week prior to completing the questionnaire) at or below each time are plotted versus clock hours after midnight. The percentiles are plotted for 6 groups: a) absolutely certain DSPD 1, b) fairly certain DSPD 2, c) questionable DSPD 3, d) unlikely or very doubtful DSPD 4–5, e) the DSPD-C, and f) a representative sample of San Diego adults.