Stats = {}
Stats.count = 0
Stats.sum = 0
Stats.sumOfSquares = 0
Stats.histo = null

Stats.add = function(x)
    self.count = self.count + 1
    self.sum = self.sum + x
    self.sumOfSquares = self.sumOfSquares + x*x
    bin = floor(x*10)
    if not self.histo then self.histo = [0]*10
    self.histo[bin] = self.histo[bin] + 1
end function

Stats.mean = function()
    return self.sum / self.count
end function

Stats.stddev = function()
    m = self.sum / self.count
    return sqrt(self.sumOfSquares / self.count - m*m)
end function

Stats.histogram = function()
    for i in self.histo.indexes
        print "0." + i + ": " + "=" * (self.histo[i]/self.count * 200)
    end for
end function

for sampleSize in [100, 1000, 10000]
    print "Samples: " + sampleSize
    st = new Stats
    for i in range(sampleSize)
        st.add rnd
    end for
    print "Mean: " + st.mean + "  Standard Deviation: " + st.stddev
    st.histogram
end for