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Finding a Z-score from a specified Area to the Right
Example: Find the Z-score such that the area to the right of Z-score is 0.4332.
This is
an inverse normal problem and the command invNorm( area,
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)
is used. In this type of problem, an area under the normal curve is given and
you are asked to find the corresponding Z-score. In this example, the area
given is the area to the right of a Z-score. The area is 0.4332. (The area
value that you enter into the TI-83 must always be area to the left of a
Z-score).
To find the Z-score corresponding to right area of 0.4332, subtract 0.4332 from 1 to obtain the area to the left of the Z-score. Press 2nd [DISTR] and select 3:invNorm( and type in .5668 , 0 , 1 ) and press ENTER.
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The Z-score that has an area to the right equal to 0.4332 is Z = .17.