Widget: Inverse Normal Probability Calculator

Find the value a that completes any of the following normal probability statements:

• Left-tail: P(X < a) = b
• Right-tail: P(X > a) = b
• Two-tail: P(X > |a|) = P(X > a AND X < -a) = b
• Confidence level: P(X < |a|) = P(-a < X < a) = b

After you input a value for a, the mean, and the standard deviation click 'Submit.' In the results you will be given the results for a left-tail, right-tail, two-tail, or confidence level probability statement. You will also have the option to select the corresponding graph.