Amit,

You can use circular statistics.  Search for a software package called Oriana or other stats software that can do this:

https://www.kovcomp.co.uk/oriana/

Many thanks Prof. Geusz. I will look at those software which performs circular statistics.

Dear Amit:

You are right, you have to use another kind of analysis, and as Michael points out above, you have to look for circular statistics. In my lab we have used the Rayleigh test (Bastchelet, E. (1981) Tests for Randomess and Goodness-of-fit.

Circular Statistics in Biology, pp. 52–83. Academic Press, New York.) to evaluate the significance of a predominant vector angle in a phase map. Check the paper attached to see how we used. Although the reference is a little bit old, you can do the math in any program you chose, is real simple and straight formard. You also may find other useful tests in that book.

Good luck!

Article The Effect of Photoperiod and Light Irradiance on the Antiox...