Table 1.

Sample size calculation for an associated factor based on some variables from a review of studies using open Epi info version 7 for cross-sectional studies.

Factors	Percentage of unexposed with outcome	Two-sided confidence level	AOR	Power	Zα/2	Ratio of unexposed to exposed	Sample size	Ref. no.
History of punctures with sharp materials	1.5	95%	5.70	80	1.96	1	336	(55)
History of dental treatment	2.2	95%	4.10	80	1.96	1	404	(36)
History of abortions	1.6	95%	4.97	80	1.96	1	392	(56)
History of home delivery	2.01	95%	4.10	80	1.96	1	440	(36)