Yes, the functions are a little more geared up for use in OCEAN scripts rather than in ADE.
To use them, you'd do:
and then use the functions as described in the comments at the top of the code. For more info on OCEAN, probably best to start with the OCEAN reference manual - <ICinstDir>/doc/oceanref/oceanref.pdf
Cadence also has a training class on OCEAN.
Alternatively, another way you can do things is to use the "save family data" option on the monte carlo form, and then use the same expression you used for your monte carlo scalar expressions in the calculator. This will give you a waveform which has the result of the expression versus the iteration number. Having done that you can use the calculator stddev function to find the standard deviation, or the average function to find the mean. Take note of the second solution number I mention above, as this describes the slight difference you'll get in the mean and standard deviation when doing it this way.