PT  - JOURNAL ARTICLE
AU  - Walter, S D
TI  - The power of a test for seasonality.
AID  - 10.1136/jech.31.2.137
DP  - 1977 Jun 01
TA  - British Journal of Preventive & Social Medicine
PG  - 137--140
VI  - 31
IP  - 2
4099  - http://jech.bmj.com/content/31/2/137.short
4100  - http://jech.bmj.com/content/31/2/137.full
SO  - Br J Prev Soc Med1977 Jun 01; 31
AB  - The power of a test of Edwards to detect seasonality or cyclic variation in the rate of an epidemiological event is derived and tabulated. A simple harmonic or sinusoidal form of variation is assumed, but the power results should also apply approximately to other situations with similar types of rate oscillation. The results may be used by investigators to determine the sample size required in order to detect seasonal variation of a given magnitude, or conversely to calculate the probability of detecting seasonality of various amplitudes with a sample of fixed size.