A study examined the link between sodium intake and blood pressure in children and adolescents
between the ages of 8 and 18. The mean systolic blood pressure (SBP) was 112.8 mm Hg among
the 636 study participants who were overweight or obese and consumed high levels of sodium,
resulting in a 95% confidence interval for this group of 110.7 to 114.9 mm Hg.
The numerical value of the margin of error for this confidence interval is____ mm Hg.