A confidence interval for the average test score in a class is given as $(72.4,79.6)$. What are the sample mean and the margin of error?

• A. $\bar{x}=76.0$   $E=3.6$
• B. $\bar{x}=76.0$   $E=2.6$
• C. $\bar{x}=75.0$   $E=3.6$
• D. $\bar{x}=75.0$   $E=2.6$

Answer: (A)