Answer:
65.5
Step-by-step explanation:
Using the relation :
Xbar ± Margin of error
Margin of Error = Zcritical * s/√n
The Zcritical value at 95% = 1.96
Hence,
Margin of Error = 1.96 * 2.5/√60
Margin of Error = 1.96 * 0.3227486
Margin of Error = 0.6326
Lower boundary = 65.5 - 0.6326 = 64.867
Upper boundary = 65.5 + 0.6326 = 66.133
(64.867 + 66.133) / 2