Cramer’s test:
The aim is to examine the stability of a long term records in terms of comparison between the overall mean of an entire record and the mean of the certain part of the record (WMO 1966).
t_(k )= √([n(N-2)/(N-n(1+r_k^2 )]r_k )
The statistics tk is distributed as ‘Student’s t’ with N-2 degress of freedom. This test may be repeated for any desired number and choice of sub periods in the whole record. The time plot of the t-value gives the pictorial representation of variability. Student’s t-test: In order to estimate trends in wind shear, temperature gradient and cyclones, simple linear regression technique was used. These trends have been tested by using Student’s t-test. The statistic, t is