TABLE 7.

Dietary supplement ingredient variability when separating supplement, lot, and sample variance components for vitamins¹

Variance component	Folic acid	Niacin	Riboflavin	Thiamin	Vitamin B-12	Vitamin B-6	Vitamin C	Vitamin E	Mean
Total pooled variance	295	174.7	628.2	243.7	490.4	214.4	125.9	126.1	287.3
Total pooled SD2	17.2	13.2	25.1	15.6	22.1	14.6	11.2	11.2	16.9
Between supplements, %	60.1	79.7	93.9	76.9	80.6	87.3	37.4	53.4	71.2
Between lots within supplements, %	32	19.8	4.5	20.9	15.3	10.2	46.9	33.7	22.9
Between samples within lots, %	7.9	0.5	1.6	2.3	4	2.5	15.7	13	5.9

¹The final regression equations were used for variance component analysis to estimate the variability between supplements, between lots within supplements, and between samples within lots. The supplement variance is an estimate of how the supplements vary around the regression line, excluding the lot and sample variances. The lot variance component is an estimate of how lots vary around the supplement mean averaged over all supplements, excluding sample variance. The sample variance component is an estimate of how samples vary around the lot mean averaged over all lots.

²Square root of variance.