Question

Assuming a 90% confidence level, the margin of error is approximately?

Answer 1

Answer:

  0.3

Step-by-step 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