stats

Confidence Interval

Margin of error, lower/upper bounds, and interval for Z- or T-methods.

Inputs

Sample Mean x̄

Sample Size n

Std Dev σ (known)

Confidence Level

Method

Use Z when σ is known or n ≥ 30

Results

Critical value Z*—

Margin of Error ME—

Lower Bound—

Upper Bound—

Interval—

ME = Z* × σ/√n · CI = x̄ ± ME