Epidemiologic Perspectives & Innovations

Table 1 Number of subjects in a simple random sample and population by gender and smoking status

From: Should adjustment for covariates be used in prevalence estimations?

	Sample			Population
	Smoking status			Smoking status
Gender	Yes	No	Total	Yes	No	Total
Male	n ₁₁	n ₁₀	n _1•	N ₁₁	N ₁₀	N _1•
Female	N ₂₁	n ₂₀	n _2•	N ₂₁	N ₂₀	N _2•
	n _•1	n _•0	n	N _•1	N _•0	N

Description	Sample Notation			Population Notation
Number of smokers	n _•1			N _•1
# of male smokers	n ₁₁			N ₁₁
# of female smokers	n ₂₁			N ₂₁
Number of non-smokers	n _•0			N _•0
# of male non-smokers	n ₁₀			N ₁₀
# of female non-smokers	n ₂₀			N ₂₀
Number of subjects	n = n_•1 + n_•0 = n_1• + n_2•			N = N_•1+ N_•0 = N_1• + N_2•
Proportion of male subjects				ω = N_1•/N
Smoking prevalence				π = N_•1/N
Male smoking prevalence				π_M = N₁₁/N_1•
Female smoking prevalence				π_F = N₂₁/N_2•

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