is $f$ always periodic? why do you need to test if the data are periodic which function is the smallest of periodic how to tell whether a function is periodic how to test whether a function is periodic what is the periodicity of an t-value? which is a test that tests for periodicity? is data a periodic or almost periodic value why is f=equidistant? what test is used to find the exact periodicity of the data what is the test to distinguish between almost periodic and periodic data? why is data $f$ very periodic what is a test to tell whether data is really periodic what is the test to distinguish between periodic and almost periodic data? when a function is always very periodic what is the purpose of a test for a function of periodicity what is a periodic function how do you test for periodicity is $f$ periodic what type of data is t_i used for in test