Figure 1 - Altman's nomogram for the calculation of sample size or power (extracted from Altman, 1982 How large a sample? in Statistics in Practice.
From the following article
Further statistics in dentistry Part 4: Clinical trials 2
A Petrie, J S Bulman & J F Osborn
British Dental Journal 193, 557 - 561 (2002) Published online: 23 November 2002
doi:10.1038/sj.bdj.4801627
Eds S. M. Gore and D. G. Altman. BMA London. Copyright BMJ Publishing Group, with permission.)
