test for possibly multimodal data. See also Circular correlation coefficient Complex normal distribution Wrapped distribution References Books on directional statistics Batschelet, E. Circular statistics in biology, Academic Press, London, 1981. . Fisher, N. I., Statistical Analysis of Circular Data, Cambridge University Press, 1993. Fisher, N. I., Lewis, T., Embleton, BJJ. Statistical Analysis of Spherical Data, Cambridge University Press, 1993. Jammalamadaka S. Rao and SenGupta A. Topics in Circular Statistics, World Scientific, 2001. Mardia, K. V. and Jupp P., Directional Statistics (2nd edition), John Wiley and Sons Ltd., 2000. Ley, C. and Verdebout, T., Modern Directional Statistics, CRC Press Taylor & Francis Group, 2017. Statistical data types Statistical theory Types of probability distributions