Statistics

Margin of Error Calculator

Find the margin of error for a mean.

Calculated Output

Margin of error 2.94

Formula: MOE = z × σ ÷ √n

Step-by-Step Breakdown

1. Values used:

2. Standard deviation = 15

3. Sample size = 100

4. Confidence level = 1.96

6. Margin of error = 2.94

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The math behind it

MOE = z × standard deviation ÷ √(sample size). Bigger samples shrink the margin.

σ 15, n 100, 95% → ±2.94.

Reduce it?

Increase the sample size (it scales with 1/√n).