Acute myocardial infarction occurring at pre-existing mild stenosis, on the image obtained 3 days before the onset of acute myocardial infarction

effect), b2 the regression coefficient for every unit increase in the patient's age and b3 the fixed estimates for patients in the study group versus the control group.The term u1j refers to the random departures or ''residuals'' at the surgeon level.This allows the j'th surgeon's line to differ from the average regression line.u1j is the level 2 random coefficient for surgeon j, or ''surgeon-effect'', which assumes a normal distribution with a mean of zero and variance sm12.