STEYX function
Returns the standard error of the predicted yvalue for each x in the regression. The standard error is a measure of the amount of error in the prediction of y for an individual x.
Syntax
STEYX(known_y's,known_x's)
Known_y's is an array or range of dependent data points.
Known_x's is an array or range of independent data points.
Remarks

Arguments can either be numbers or names, arrays, or references that contain numbers.

Logical values and text representations of numbers that you type directly into the list of arguments are counted.

If an array or reference argument contains text, logical values, or empty cells, those values are ignored; however, cells with the value zero are included.

Arguments that are error values or text that cannot be translated into numbers cause errors.

If known_y's and known_x's have a different number of data points, STEYX returns the #N/A error value.

If known_y's and known_x's are empty or have less than three data points, STEYX returns the #DIV/0! error value.

The equation for the standard error of the predicted y is:
where x and y are the sample means AVERAGE(known_x’s) and AVERAGE(known_y’s), and n is the sample size.
Example
The example may be easier to understand if you copy it to a blank worksheet.
How to copy an example

Create a blank workbook or worksheet.

Select the example in the Help topic.
Note Do not select the row or column headers.
Selecting an example from Help

Press CTRL+C.

In the worksheet, select cell A1, and press CTRL+V.

To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.

