Standard Deviation(dev) bug in kdb/q 3.2?

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1

I am using KDB+ 3.2 32bit edition, when I run dev 10 343 232 55 , I got 155.1322.

But in the reference it says: 134.3484. Here is the link http://code.kx.com/wiki/Reference/dev

Is it a bug? Can you help.

2

since v3.2 2014.02.07

var and dev now use N-1 instead of N for calcs.

3

Btw, in kdb+3.2 2015.01.12
we’ve reverted dev,var to population

and added sdev,svar scov for sample.

4

In kdb+3.2 2015.01.20:

sdev 10 343 232 55

'sdev

On Tuesday, January 13, 2015 at 5:14:08 AM UTC+8, Charles Skelton wrote:

Btw, in kdb+3.2 2015.01.12
we’ve reverted dev,var to population

and added sdev,svar scov for sample.

5

kdb+ depends on 2 files - the q binary and the associated q.k for that release.
svar is defined in q.k; I expect that you did not copy over the new q.k into you QHOME dir or $HOME/q.

The next release will have it redefined as

svar:{(n*var x)%-1+n:(#x)-+/^x};

anyway.

thanks

6

Of courses. Thanks Charles