How we worked it out
Updated as you change the numbers.
- Two-tailed: split α between the tails, so the values are the α/2 and 1 − α/2 quantiles.
Method and assumptions
Quantiles come from the inverse of each distribution’s cumulative distribution function, computed numerically to at least four decimal places.
Questions
What is the z critical value for a 5% two-tailed test?
±1.96 (more precisely 1.9600). For t with 10 degrees of freedom it is ±2.2281.
Sources
Method and figures checked on . Every worked answer on this page is covered by an automated test. Found a mistake? Tell us.