When the standardizing function doesn't return a standard deviation of 1
<p>Given:</p>

<pre><code>stdized = function(x)
{
    return (x-mean(x)/sd(x))
}
</code></pre>

<p>According to the <a href="https://en.wikipedia.org/wiki/Feature_scaling#Standardization" rel="nofollow">wiki page describing feature standardisation</a>, the stdev of the output of this function should be 1. Yet:</p>

<pre><code>&gt; sd(stdized(c(1,2,3,4,5)))
[1] 1.581139
</code></pre>

<p>Why so?</p>