Statistics How To

Area between two z values on opposite sides of mean

normal distribution curve index)> area between two z values on opposite sides

Watch the video or read the steps below:

How to find the area between two z values on opposite sides of the mean

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 One Side of the Mean.

area between two z values on opposite sides

normal distribution with z-scores on opposite side of 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).

z0.000.010.020.030.040.050.060.070.080.09
0.00.00000.00400.00800.01200.01600.01990.02390.02790.03190.0359
0.10.03980.04380.04780.05170.05570.05960.06360.06750.07140.0753
0.20.07930.08320.08710.09100.09480.09870.10260.10640.11030.1141
0.30.11790.12170.12550.12930.13310.13680.14060.14430.14800.1517
0.40.15540.15910.16280.16640.17000.17360.17720.18080.18440.1879
0.50.19150.19500.19850.20190.20540.20880.21230.21570.21900.2224

Step 2: Add the values you found in step 1 together.

That’s it!

*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.

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Area between two z values on opposite sides of mean was last modified: July 17th, 2015 by Stephanie

2 thoughts on “Area between two z values on opposite sides of mean

  1. Stephanie

    Hi, Joe,
    Can you post your question on the forum? Unfortunately, I don’t have the time to answer math questions here.
    Thanks,
    Stephanie

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