To find the area between two negative *z* scores is, by symmetry of the bell curve, equivalent to finding the area between the corresponding positive *z* scores. Use the standard normal distribution table to look up the areas that go with the two corresponding positive *z* scores. Next subtract the smaller area from the larger area.

For example, finding the area between *z*_{1} = -2.13 and *z*_{2} = -.45, is the same as finding the area between *z*_{1}^{*} = .45 and *z*_{2}^{*} = 2.13. From the standard normal table we know that the area associated with *z*_{1}^{*} = .45 is .674. The area associated with *z*_{2}^{*} = 2.13 is .983. The desired area is the difference of these two areas from the table: .983 - .674 = .309.