The z-Score Calculation Form performs z-Score calculations upon entry of a Mean, Standard Deviation, and X value or Area. The z-Score and the proportion (displayed in proportion, percent, parts per million, and parts per billion) above and below X or the value corresponding to the upper-tail area entered, for a normally distributed population, will be displayed.
The z-score is calculated by the following formula.
Menu
- File provides the ability to Print the Graph and Text, or return to the Main Form.
- Edit allows Editing Output Text by cutting, copying, pasting, and undoing entry, and provides the abililty to Copy the Graph to the Windows Clipboard.
- View: Provides the ability to enlarge the Form size for easier viewing.
- Help provides access to this Website.
Speed Buttons
These buttons provide quick access to the following tasks.
Returns to the Main Form.
Prints the Graph and Text.
Copies the Graph to the Clipboard.
Copies the Selected Text to the clipboard.
Enlarges/Reduces Form size for easier viewing.
Brings up the Main Form.
Brings up the Help file.
Hides the form.
Mean
Enter the population Mean here.
Standard Deviation
Enter the population Standard Deviation here.
X-Value
Enter the X-value of interest here.
Decimal Place Change
Changes the number of decimal places, from 0 to 9. Change may be made by selecting and typing in the number, or by using the incrementing buttons.
Action Button
Performs calculations and displays output.
Output Text
The calculation output is displayed here when 
is clicked. You may save, print, edit, cut, copy, and paste text in this area.
is clicked. You may save, print, edit, cut, copy, and paste text in this area.Distribution Graph
The distribution graph is displayed here. The tail areas will be shown in Red. Double clicking on this graph will copy it to the clipboard.
Proportion Selection
The Area may be input or output as a proportion, percent, parts per million (ppm), or parts per billion (ppb) when selected.
Area or Value
Select if an area or value is wanted for output.
z Only
Check this to enter or find only z-scores.