What number is significant for a z-score in statistics?

Answer 1

It depends on where you have set your alpha. To be significant at an alpha of .05 (typical), the z-score must exceed 1.96. Here, we are accepting a 5% error rate. To be significant at an alpha of .01 (more stringent/restrictive/conservative), the z-score must exceed 2.58. At an alpha of .01, you are only accepting a 1% error rate. If you are doing multiple tests of significance, you'll likely want to use this more conservative alpha (or do a "Bonferroni correction," dividing .05 by the actual number of significance tests you perform). Hope this helps!