We found a matchYour institution may have access to this item. Find your institution then sign in to continue.TitleStatistics Notes: Units of analysisAuthorsAltman, D. G; Bland, J M.PublicationBMJ, 1997, Vol 314, Issue 7098, p1874ISSN0959-8138Publication typearticleDOI10.1136/bmj.314.7098.1874