MONICA Manual, Part III, Section 2

APPENDIX 1. Example of calculation of the pool mean () and standard deviation (S_t).

Cholesterol in mmol/l

Date	Pool vial number	Determination 1		Determination 2
		Xi	Xi2	Xi	Xi2
	1	6.31	39.8161	6.41	41.0881
	2	6.47	41.8609	6.21	38.5641
	3	6.26	39.1876	6.21	38.5641
	4	6.21	38.5641	6.41	41.0881
	5	6.41	41.0881	6.31	39.8161
	6	6.36	40.4496	6.36	40.4496
	7	6.21	38.5641	6.26	39.1876
	8	6.26	39.1876	6.36	40.4496
	9	6.21	38.5641	6.26	39.1876
	10	6.23	38.8129	6.44	41.4736
	11	6.44	41.4736	6.23	38.8129
	12	6.26	39.1876	6.36	40.4496
	13	6.21	38.5641	6.26	39.1876
	14	6.26	39.1876	6.21	38.5641
	15	6.21	38.5641	6.36	40.4496
	16	6.31	39.8161	6.41	41.0881
	17	6.41	41.0881	6.21	38.5641
	18	6.21	38.5641	6.26	39.1876
	19	6.21	38.5641	6.47	41.8609
	20	6.41	41.0881	6.31	39.8161
		125.86	-	126.31	-
			792.1926		797.8491

Calculation of the mean:       

Calculation of standard deviation:

Calculation of the coefficient of  variation: