15_6.py

def makePlot(xVals, yVals, title, xLabel, yLabel, style, logX = False, logY = False):
    pylab.figure()
    pylab.title(title)
    pylab.xlabel(xLabel)
    pylab.ylabel(yLabel)
    pylab.plot(xVals, yVals, style)
    if logX:
        pylab.semilogx()
    if logY:
        pylab.semilogy()

def runTrial(numFlips):
    numHeads = 0
    for n in range(numFlips):
        if random.choice(('H', 'T')) == 'H':
            numHeads += 1
    numTails = numFlips - numHeads
    return (numHeads, numTails)

def flipPlot1(minExp, maxExp, numTrials):
    """minExpとmaxExpは、minExp<maxExpを満たす正の整数
    numTrialsは正の整数とする
    2**minExpから2**maxExp回のコイン投げをnumTrials回
    行った結果の要約をプロットする"""
    ratiosMeans, diffsMeans, ratiosSDs, diffsSDs = [], [], [], []
    xAxis = []
    for exp in range(minExp, maxExp+1):
        xAxis.append(2**exp)
    for numFlips in xAxis:
        ratios, diffs = [], []
        for t in range(numTrials):
            numHeads, numTails = runTrial(numFlips)
            ratios.append(numHeads/numTails)
            diffs.append(abs(numHeads-numTails))
        ratiosMeans.append(sum(ratios)/numTrials)
        diffsMeans.append(sum(diffs)/numTrials)
        ratiosSDs.append(stdDev(ratios))
        diffsSDs.append(stdDev(diffs))
    numTrialsString = '(' + str(numTrials) + ' Trials)'
    title = 'Mean Heads/Tails Ratios' + numTrialsString
    makePlot(xAxis, ratiosMeans, title, 'Number of flips', 'Mean Head/Tails', 'ko', logX = True)
    title = 'SD Heads/Tails Ratios' + numTrialsString
    makePlot(xAxis, ratiosSDs, title, 'Number of Flips', 'Standard Deviation', 'ko', logX = True, logY = True)