- Douglas G Altman, heada,
- J Martin Bland, professor of medical statisticsb
- a ICRF Medical Statistics Group, Centre for Statistics in Medicine, Institute of Health Sciences, PO Box 777, Oxford OX3 7LF
- b Department of Public Health Sciences, St George's Hospital Medical School, London SW17 0RE
- Correspondence to: Mr Altman.
As we have noted before, many statistical methods of analysis assume that the data have a normal distribution.1 When the data do not they can often be transformed to make them more normal.2 Readers of published papers may wish to be reassured that the authors have carried out an appropriate analysis. When authors present data in the form of a histogram or scatter diagram then readers can see at a glance whether the distributional assumption is met. If, however, only summary statistics are presented—as is often the case—this is much more difficult. If the summary statistics …