The impact of gender mix on the reported efficacy of aspirin in reducing non-fatal myocardial infarction risk. The regression line is weighted by the reciprocal of the standard error (1/SE) of the relative risk of each trial. The diameter of each circle is proportional to 1/SE of each trial.
Yerman et al. BMC Medicine 2007 5:29 doi:10.1186/1741-7015-5-29