September 2014
Intermediate to advanced
236 pages
4h 17m
Japanese
Content preview from Think Bayes ―プログラマのためのベイズ統計入門
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92
■
8
章
観察者バイアス
時間（分）
z
zb
y
図 8-2 z, zb, 乗客から見た待ち時間yのCDF
8.4
待ち時間を予測する
元々の動機となった質問に戻ろう。私が駅に着いて、
10
人待っているのがわかった
と仮定しよう。次の電車が来るまでの待ち時間はどのくらいと予測するか。
いつものように、この問題の一番やさしいものから始めて、難しいのに移ることにし
よう。実際の分布
z
が与えられており、乗客の到着率
λ
は、
1
分ごとに
2
人と仮定する。
この場合、次のことが行える。
1.
z
の分布を使って、乗客から見た電車の間隔
zp
の事前確率分布を求める。
2.
次に、乗客数を使って、直前の電車が発車してからの経過時間
x
の分布を推測す
る。
3.
最後に、関係
y = zp - x
を使って、
y
の分布を求める。
第
1
ステップとしては、乗客数を考慮した事前確率
zp
、
x
、
y
の分布をカプセル化す
る
WaitTimeCalculator
を作る。
8.4
待ち時間を予測する
■
93
wtc = WaitTimeCalculator(pmf_z)
ここで
pmf_z
は、与えられた時間間隔の分布である。
次のステップでは、（次に定義する）
ElapsedTimeEstimator
を作る。これは、
x
の事
後確率分布と
y
の推定分布とをカプセル化
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.