diff options
Diffstat (limited to 'lib/overwrite.rb')
-rw-r--r-- | lib/overwrite.rb | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/lib/overwrite.rb b/lib/overwrite.rb index be90c56..c92ad2b 100644 --- a/lib/overwrite.rb +++ b/lib/overwrite.rb @@ -96,6 +96,16 @@ class Array self.inject{ |sum, el| sum + el }.to_f / self.size end + def sample_variance + m = self.mean + sum = self.inject(0){|accum, i| accum +(i-m)**2 } + sum/(self.length - 1).to_f + end + + def standard_deviation + Math.sqrt(self.sample_variance) + end + end module URI |