Answer:
The margin of error is approximately 0.39.
Explanation:
Formular for the margin of error is
Margin of error = z* (sd/√n)
Where z* is 95% confidence level = 1.96, sd is 1.8 and n is 81
Margin of error = 1.96 (1.8/√81)
= 1.96(1.8/9)
= 1.96*0.2
= 0.392