Answer:
0.3
Explanation:
The margin of error is calculated as ...
(standard deviation)/√(sample size) × (z*-score)
where the z*-score is chosen based on the desired confidence level.
Here, you have ...
- standard deviation = 2.7
- √(sample size) = √225 = 15
- z*-score for 90% confidence level = 1.645
Putting these values in the above expression for margin of error gives ...
2.7/15·1.645 = 0.2961 ≈ 0.3