XL: LINEST or REGRESS Error Value When X-Values Dependent

• Microsoft Excel 98 Macintosh Edition
• Microsoft Excel 97 for Windows
• Microsoft Excel for Windows 95, versions 7.0, 7.0a
• Microsoft Excel for Windows NT, version 5.0
• Microsoft Excel for Windows, versions 3.x, 4.x, 5.0, 5.0c
• Microsoft Excel for the Macintosh, versions 3.x, 4.0, 5.0, 5.0a

SYMPTOMS

In Microsoft Excel, the LINEST, TREND, and REGRESS functions (the REGRESS function is available in the Analysis ToolPak add-in macro) may return a #NUM! error value.

CAUSE

This problem will occur if any set of known x-values is dependent on any other set of known x-values.

MORE INFORMATION

A set of known x-values is considered to be dependent on another set of known x-values when the first set is a multiple of the second set. For example, consider the following four sample number sets:

   Set A       Set B          Set C          Set D
   ------------------------------------------------

   1           1              4              7
   2           2              8              9
   3           3              12             11
   4           4              16             13
   5           5              20             15

   Set B is dependent on Set A (and A is dependent on B) because each
   element in Set B is equal to its corresponding element in Set A
   (Set A*1=Set B).

   Set C is dependent on Set A (and A is dependent on C) because each
   element in Set C is equal to four times its corresponding element
   in Set A (Set A*4=Set C).

   Set D is not dependent on any of the other sets (and the other sets
   are not dependent on Set D) because it is not an even multiple of
   any of the other sets.

REFERENCES

"Microsoft Excel Function Reference," version 4.0, pages 254-258 "Microsoft Excel Function Reference," version 3.0, pages 138-141