To determine the margin of error for the given 80% confidence interval (200, 240), follow these steps:
1. Identify the bounds of the confidence interval:
- The lower bound is 200.
- The upper bound is 240.
2. Calculate the range of the confidence interval:
- Subtract the lower bound from the upper bound:
[tex]\[ \text{Range} = 240 - 200 = 40 \][/tex]
3. Determine the margin of error:
- The margin of error is half of the range of the confidence interval:
[tex]\[ \text{Margin of Error} = \frac{\text{Range}}{2} = \frac{40}{2} = 20 \][/tex]
Thus, the margin of error is 20.
The correct answer is:
D. 20
