Refactor with aggregate gem

stats.rb

# Using the aggregate gem (http://www.gemcutter.org/gems/aggregate),
# run the given block +num+ times and then print out the mean, min,
# max, std_dev, and histogram of the run duration. For example:
#
# irb> stats(100, 0, 10, 1) { sleep(rand / 100) }
# mean:   5.99ms
# min:    1.49ms
# max:    9.28ms
# stddev: 2.54ms
# value |------------------------------------------------------------------| count
#     0 |@@                                                                |     2
#     1 |@@@@@@@@@@@@@                                                     |    13
#     2 |@@@@@@@@@@                                                        |    10
#     3 |@@@@@@@@@@                                                        |    10
#     4 |@@@@@@@@@@@@                                                      |    12
#     5 |@@@@@@@@@@@                                                       |    11
#     6 |@@@@@@@@@@@@@                                                     |    13
#     7 |@@@@@                                                             |     5
#     8 |@@@@@@@@@@@@                                                      |    12
#     9 |@@@@@@@@                                                          |     8
# Total |------------------------------------------------------------------|    96

require 'rubygems'
require 'aggregate'

def stats(num, low=nil, high=nil, width=nil)
  records = Aggregate.new(low, high, width)
  num.times do
    t0 = Time.now
    yield
    records << (Time.now - t0) * 1000
  end

  puts "mean:   %1.2fms" % records.mean
  puts "min:    %1.2fms" % records.min
  puts "max:    %1.2fms" % records.max
  puts "stddev: %1.2fms" % records.std_dev

  puts records.to_s
end