[R] Sandard deviation calculation

(Ted Harding) Ted.Harding at manchester.ac.uk
Mon Oct 26 15:28:48 CET 2009

On 26-Oct-09 09:44:55, ms.com wrote:
> Dear all
> I am trying to learn R
> I was trying to calculate standard deviation
> here are the commands and outputs in R
>> sd(Ht_cm[type=='SD'])[1] 3.283605
>> sd(Ht_cm[from_treeline=='above'])[1] 16.83289
>> sd(Ht_cm[type=='SD'][from_treeline=='above'])[1] NA
> the problem is that, i could not understand why the third command could
> not give any result.
> please help me out
> thanking you
> Regard
> MS
> Nepal

This suggests that either you have only one observation in the
third case, or there is an NA amongst them.

What are the values of






The answers to these may provide adequate clues to diagnose
the reason.


E-Mail: (Ted Harding) <Ted.Harding at manchester.ac.uk>
Fax-to-email: +44 (0)870 094 0861
Date: 26-Oct-09                                       Time: 14:28:38
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