What to do for “huge z-values”? They do sometimes turn up, especially when the evidence for a hypothesis test is very strong one way or the other. Anyway, just use a spreadsheet to find your p-values instead of the standard normal table. The following formulas work for finding p-values using a spreadsheet (and work for any size z-values actually, not just “huge” ones):
1) left tailed test, use
For example if
2) right tailed test, use
For example if
3) two tailed test, and z is negative, use
For example if
4) two tailed test and z is positive use
For example if
Of course any time the z-value is “huge” that means the p-value is going to be small.
And remember a very small p-value means very strong evidence against the null hypothesis .
You still want to find the actual p-value though and state what it is when you do a hypothesis test even if you do know because the z-value is “huge” it is going to lead to very strong evidence against .
