◊ A margin of error is a number or percentage that shows how accurate a measurement is.误差幅度
The poll indicates that the President is supported by 54 percent of the voters, with a margin of error of 3 percent. [=it is possible that as few as 51 percent or as many as 57 percent of the voters support the President]民意调查显示有54%的选民支持总统,误差幅度为3%。