Standard Deviation When Only One Record

[Cheryl Lamonds]

Access 97. Summary query. Field value is 0 or 1 and have StDev in the total
line. Within a group, if there is only one record I am not getting a value
for standard deviation. Works fine as long as there is more than one record
within the group. I could probably manipulate a value into that field but
I'm not sure I could do it within the same query. Is this how it is
supposed to be?

 

[Douglas J. Steele]

From the Help file:

"If the underlying query contains fewer than two records (or no records, for
the StDevP function), these functions return a Null value (which indicates
that a standard deviation can't be calculated)."

 

[scubadiver]

You may have realised by now that standard deviation is based on the spread
of data from the mean. It can't be calculated with one record !!