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Resolution: standard / high Figure 1.
Relationship between virtual flight path and Z-score value. To obtain Z-scores (shown upper right of each graph), flight data for each butterfly tested in
the flight simulator were analyzed using a Rayleigh test. Z, which is the critical value for the Rayleigh test, is calculated from the following
formula: Z = nr2, where n is the number of observations and r is the magnitude of the mean vector. Only butterflies with a Z-score 500 or above have a flight path that shows clear directionality. Virtual flight
paths were constructed by starting in the center of the square and plotting each direction
interval consecutively as one unit length [5].
Zhu et al. BMC Biology 2009 7:14 doi:10.1186/1741-7007-7-14 |