Margin of Error Statistics Example 3

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Example 3

hard
A 95% CI for a mean is 50±350 \pm 3. What is the margin of error, and what would it be if the sample size were quadrupled?

Solution

  1. 1
    Step 1: The margin of error is 3.
  2. 2
    Step 2: Quadrupling nn halves the ME: 32=1.5\frac{3}{2} = 1.5.

Answer

ME = 3. With quadrupled sample size, ME = 1.5.
Understanding the relationship between sample size and margin of error helps researchers plan studies with the desired level of precision.

About Margin of Error

The margin of error is the maximum expected difference between a sample statistic and the true population parameter, typically expressed as a plus-or-minus value. It equals half the width of a confidence interval and decreases as sample size increases.

Learn more about Margin of Error →

More Margin of Error Examples

Example 1 hard

A poll of 400 voters found 55% support a policy. Calculate the margin of error for a 95% confidence

Example 2 hard

How does quadrupling the sample size affect the margin of error?

Example 4 hard

If the confidence level is increased from 90% to 99% while the sample size and variability stay the

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