class DRbDump::Statistic
Stores the minimum, maximum, mean, count and standard deviation for a set of values but not the values themselves.
Attributes
average[R]
The mean of all values
count[R]
The number of items in the set
max[R]
The maximum value added
maximum[R]
The maximum value added
mean[R]
The mean of all values
min[R]
The minimum value added
minimum[R]
The minimum value added
Public Instance Methods
add(value)
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Adds value
to the set of values. Returns the number of values.
# File lib/drbdump/statistic.rb, line 38 def add value @min = value if value < @min @max = value if value > @max @count += 1 delta = value - @mean @mean += delta / @count @M_2 += delta * (value - @mean) @count end
sample_variance()
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The sample variance for all values
# File lib/drbdump/statistic.rb, line 68 def sample_variance sv = @M_2 / (@count - 1) return 0.0 if sv.nan? sv end
standard_deviation()
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The standard deviation of all values
# File lib/drbdump/statistic.rb, line 77 def standard_deviation Math.sqrt sample_variance end
to_a()
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An array containing the number of values in the set, the mean and the standard deviation
# File lib/drbdump/statistic.rb, line 85 def to_a [@count, @min, @mean, @max, standard_deviation] end