Knowledge Base

Solution 34508: Computing the Z-Score on the TI-83 Plus and TI-84 Plus Family of Graphing Calculators. 

How do I compute the Z-score on the TI-83 Plus and TI-84 Plus family of graphing calculators?

A Z-score is a value obtained when data from a symmetric distribution is standardized. The formula for determining the Z-score is:

z=(x-μ)/σ

Where x is the observation, μ is the mean and σ is standard deviation.

A standard observation is used to determine how many standard deviations the original observation falls from the mean. Z-scores can be looked up in a table (z-table) to find the area under the standard normal curve (or probability) to the left of the z-value.

The area under the standard normal curve for a z-value of .1 can be found by entering the following:

• Set your window settings, by pressing [WINDOW] and setting your values to xmin = - 5, xmax = 5, ymin = -.1 and ymax = .5.



• Press [2nd] [CATALOG] [S] and locate the ShadeNorm( command and press [ENTER].
• Press [(-)] [9] [9] [,] [.] [1] [)].



• Press [ENTER].

The probability associated with a Z-score of .1 is shown in the bottom-left corner.

Please see the TI-83 Plus and TI-84 Plus Family guidebooks for additional information.

Last updated: 7/29/2024