normal distribution curve index)> area between two z values on opposite sides
How to find the area between two z values on opposite sides
If you want to find the area between two z scores, the technique will differ slightly depending on if you have two z scores on one side of the mean or on opposite sides of the mean. This article will show you how to find the area between two z scores on opposite sides of the mean. If you have z scores on the same side, see: Area Between Two Z Values on Opposite Sides of the Mean.
Step 1: Look in the z-table for the z-scores by finding the intersections of both scores individually. For example, you might be asked to find the area between two z values of -0.46 and +1.16, so look up both numbers: 0.46 (see note below about absolute values) and 0.16. The table below shows the z-table value for 0.46 (0.4 in the left hand column and 0.06 in the top row. The intersection = .6772).
Step 2: Add the values you found in step 1 together.
*note. Bell curves are symmetrical, so ignore negative z-values and just look up their absolute values. For example, if you want to find the area between two z values of -3 and -4, look up 3 and 4.