Figure 5 : Scatter plot showing the relationship between the phase shift of the master, internal, circadian clock (assessed by the DLMO) due to the 9-hour delay of zeitgebers and the free-running circadian period (τ).

From: Circadian rhythms of European and African-Americans after a large delay of sleep as in jet lag and night work

Figure 5

N = 45. Filled circles represent African-Americans (N = 23) and open circles represent European-Americans (N = 22). Subjects with longer periods had larger phase delays. The diagonal line represents a linear fit of the data.