Question 1 of 40 An 80% confidence interval is found to be (12, 20). What is the margin of
error?
O A. 8
O B. 3.2
O C. 6.4
O D. 4
SUBMIT

Explanation:

The width of the confidence interval is 20-12 = 8 units. That cuts in half to get 8/2 = 4 which is the margin of error.

The center of the confidence interval is (12+20)/2 = 32/2 = 16. Add four onto this to get 16+4 = 20, which is the right endpoint. Subtract four from the center to get 16-4 = 12, which is the left endpoint.

Effectively, it's like saying "an archer aims for the value 16 on the number line, and the arrow could land as high as 20 or as low as 12".