Using the z-table (Table E) find the critical value (or values) for a = .018 left tailed test.
statistics - PsyDAG, Wednesday, April 30, 2008 at 1:37pm
Assuming that Table E is the distribution of scores/areas within a normal distribution, look for the Z score that has .018 in the smaller portion. This would give you the Z score for a one-tailed test, regardless of the direction.
I hope this helps. Thanks for asking.