How do I find the area under the normal distribution curve given the z-score or interval?

1 Answer
marfre
May 24, 2017

The total area under a normal curve = 1. Since the mean = 0, negative z-scores give the area #< 0.5# and positive z-scores yield areas #> 0.5 " and " < 1.0#

Explanation:

The total area under a normal curve = 1.

The mean = 0. Negative z-scores represent areas less than 0.5.

Positive z-scores represent areas above the mean that have areas #> 0.5 " and " < 1.0#

For example if the z-score #= -2.23#, from the z-table #0.0129# is the area under the normal distribution curve: #1.29 %#

If the z-score #= 1.64#, from the z-table #0.9495# is the the area under the normal distribution curve: #94.95 %#

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