CorrectionBMJ 1996; 313 doi: http://dx.doi.org/10.1136/bmj.313.7059.744a (Published 21 September 1996) Cite this as: BMJ 1996;313:744
Statistics Notes: Measurement error proportional to the mean
A typesetting error occurred in Note 23 (13 July, p 106). Throughout the text the symbol (sigma) should have been s, to be consistent with the previous two notes. Also the first reference should have been to note 21 (on measurement error, republished above), not note 22 (on measurement error and correlation coefficients, 6 July, p 41).