Agilent Technologies Infiniium 8000A Programmer's Reference Manual page 550

Query
Returned Format
<value> The percentage of points within one standard deviation of the mean of the
<result_state> If SENDVALID is ON, the result state is returned with the measurement result.
Example
Measure Commands
HISTogram:M1S
:MEASure:HISTogram:M1S? [<source>]
The :MEASure:HISTogram:M1S? query returns the measurement of the
percentage of points within one standard deviation of the mean of the histogram.
[:MEASure:HISTogram:M1S]<value>[,<result_state>]<NL>
histogram.
Refer to the MEASure:RESults command, for a list of the result states.
This example returns the percentage of points within one standard deviation of
the mean of the current histogram and prints the result to the computer's
screen.
10 OUTPUT 707;":SYSTEM:HEADER OFF"
20 OUTPUT 707;":MEASURE:HISTOGRAM:M1S? WMEMORY1"
30 ENTER 707;Histm1s
40 PRINT Histm1s
50 END
23-52
!Response headers off