Finding Greater than Probabilities
Our Z-Table only shows areas to the left of a given number. Remember that the total area under the curve equals one and that the curve is symmetric.
Therefore, we can say that P(Z> #) = 1 – P(Z<#).
The total area under the curve minus the area less than the given number equals the area greater than the given number. The following describes this pictorially: minus equals
Finding the Probability that Z is Greater than a Negative Number (Z > -#)
1.) Look up the given negative number on the outside of the Standard Normal
Probabilities Table (Z-Table). For example, to look up Z > -3.35, find -3.3 on the left-hand column and .05 in the top row.

2.) Find the corresponding area within the table where the row and column meet.
This area gives the probability that Z is less than the negative number. In this case,
P(Z< -3.35) = .0004.
3.) This yields the probability that z is less than –3.35, but we are trying to find the probability that z is greater than
–3.35. Therefore, we subtract the probability that we found in step two from 1. In this example, the probability that z is greater than –3.35 is P(Z>-3.35) = 1 – P(Z<-3.35) = 1 – .0004 = .9996.
Finding the Probability that Z is Greater than a Positive Number (Z > #)
1.) Look up the given positive number on the outside of the Standard Normal
Probabilities Table (Z-Table). For example, to look up Z > 3.35, find 3.3 on the left-hand column and .05 in the top row.
2.) Find the corresponding area within the table where the row and column meet.
This area gives the probability that Z is less than the positive number. In this case,
P(Z< 3.35) = .9996.
3.) This yields the probability that z is less than 3.35, but we are trying to find the probability that z is greater than 3.35. Therefore, we subtract the probability that we found in step two from 1. In this example, the probability that z is greater than
3.35 is P(Z>3.35) = 1
– P(Z<3.35) = 1 – .9996 = .0004.