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-rwxr-xr-xstddev8
1 files changed, 7 insertions, 1 deletions
diff --git a/stddev b/stddev
index 2634f63..6a29e74 100755
--- a/stddev
+++ b/stddev
@@ -5,6 +5,7 @@ require 'trollop'
conf = Trollop::options do
banner "stddev [-r <d>] < <one number per line>"
opt :round, "Number of digits after decimal point.", :type => :int, :default => -1
+ opt :corrected, "corrected stddev", :type => :bool, :default => false
end
sum = 0.0
@@ -24,7 +25,12 @@ cached.each { |v|
var += (avg - v)**2
}
-stddev = Math.sqrt(var/i.to_f)
+stddev = 0
+if conf[:corrected]
+ stddev = Math.sqrt(var/(i.to_f-1))
+else
+ stddev = Math.sqrt(var/i.to_f)
+end
if conf[:round] >= 0
puts stddev.round conf[:round]