Standard deviation for a set of values

[#1]

Hi All,

I am trying to calculate the Standard deviation for a set of values.

the values are like

MT1 MT2 MT3 MT4 MT5 date Room

1 2 3 4 5 15th July A

12 32 5 8 9 15th July B

1 20 1 4 7 15th July A

now i want to take Std dev of all the values MT1 to MT5 when the room name is same.

I tried Stdev (aggr(sum(MT1),Room))+Stdev (aggr(sum(MT2),Room))+Stdev (aggr(sum(MT3),Room))+Stdev (aggr(sum(MT4),Room))+Stdev (aggr(sum(MT1),Room))

Also one more thing to mention here is these MT1 to MT5 values could be null as well.

But it doesn't work..can someone plz help. Thanks in Advance

Regards,

Himanshu

[johnw]

One approach is to use a crosstable to load the values into a single field. See the attached. I also thought I might be able to use rangestdev(MT1,MT2,MT3,MT4,MT5), but as you can see, it's not producing the correct value. There's probably something like that that would work, though.