title: Significance tests. Part 3.
abstract: A discussion of basic parametric statistical tests of sample proportions and frequencies is concluded with a description of the chi-squared test. The treatment of distribution-free or non-parametric data is then illustrated with examples of the sign test and Wilcoxon's two-sample rank test.
authors.forename: J S
authors.initials: JS
authors.lastname: Bulman
authors.forename: J F
authors.initials: JF
authors.lastname: Osborn
mesh_terms: D002648:Child; D003773:Dental Plaque / Q000517:prevention & control; D003802:Dentifrices / Q000627:therapeutic use; D006801:Humans; D009910:Oral Hygiene; D012107:Research Design; D013223:Statistics as Topic
chemical_list: D003802:Dentifrices