Mercury (Hg) poisoning is a serious problem among children, and amalgam dental fillings are thought to be one source of mercury. The chart above shows the average amount of mercury in urine for a group of children who were randomly assigned to receive amalgam fillings (black dots) and composite fillings (white dots) [Woods et al. EHP 115(10), 2007]. The error bars show the 95% confidence intervals. Approximately what was the 95% confidence interval for amalgam fillings in follow-up year 2