Confidence Interval... - Statistics With Confidence:

To determine a basic confidence interval for a mean, you generally need:

: The amount of "plus or minus" added to the sample mean. It depends on the standard deviation and the sample size. How to Calculate and Report CIs Statistics with Confidence: Confidence Interval...

: Often set at 90%, 95%, or 99%. A higher level (e.g., 99%) creates a wider, more inclusive interval. To determine a basic confidence interval for a