Cumulative standard deviation: Difference between revisions
→{{header|R}}: Solution that gives every result so far, rather than just the final result.
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ReeceGoding (talk | contribs) (→{{header|R}}: Solution that gives every result so far, rather than just the final result.) |
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uncorrectedsd(testdata) #2</lang>
==="Running" SD===
If we desire a solution that gives every "running" standard deviation for each input, rather than only giving one number as our final output, we can do the following. To make this differ from previous solutions, we will not have our code make any mention of missing values, and we will show off R's Reduce and sapply.
<lang r>biasedSd<-function(data)#Once again, we have to make a standard deviation function from scratch.
{
sqrt(mean((data-mean(data))^2))
}
cumSd<-function(data)
{
sapply(Reduce(c,data,accumulate = T), biasedSd)
}</lang>
{{out}}
<pre>> cumSd(c(2, 4, 4, 4, 5, 5, 7, 9))
[1] 0.0000000 1.0000000 0.9428090 0.8660254 0.9797959 1.0000000 1.3997084 2.0000000</pre>
=={{header|Racket}}==
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