q**j
发帖数: 10612 | 1
昨天有高人说我统计没学好。说的很对，惭愧得很。昨天晚上我借了一本Cassella and
Burger 2nd edition （开本田的没钱，你懂的。）仔细看了看。结果还是没明白统计
怎么一回事情。好在上海淀走读高中老师给教过一点概率，就试着分析一下，如有不对
请高手指点。
Scenario 1:
如果假设Volvo和本田同样安全，i.e.，任选一对车比，本田1/3胜，1/3平，1/3负。要
本田四次都不输的概率是多少？
这个情形比较简单，每次不输的概率是2/3，所以四次就是16/81，20%左右。所以如果
两个车厂同样安全，iihs搞这样的调查，每五次才可以拿到一次这样的结果。平心而论
，哪个车牌子更安全，这个事实永远是未知的。所以我们买车的时候也多少是个赌博。
简单说，一个追求安全的人，到底应该压本田还是Volvo，事实告诉我们压本田有80%可
能性是对的，Volvo 20%。尼玛，要是Vegas有这么一个游戏，我肯定all in了。
Scenario 2:
如果假设Volvo和本田同样安全，i.e.，任选一对车比，本田1/3胜，1/3平，1/3负。要
本田三胜不负的概率是多少？
这个对没有文化的本田车主比较难，我请教了一个Nisssan车主才高明白。法国车主么
，数学是杠杠的。他告诉我一共有c(4,3)个方式出现这个结果。c(4,3)是什么我不知道
，法国车主告诉我这个是4，肯定没错了。剩下简单，三次要赢是（1/3）三次方乘2/3
。反正总共下来就是8/81。看见这玩意我顿时呆了。小于10%的偶然事件。Cassella
and Burger二佰多页里面好像说这个算是statistically significant了吧？来来来，
LeopardLeo你跟我一起念一遍：
We can reject the null hypothesis that Volvo is as safe as Honda with 10%
statistical significance. 我告诉你numbers do not lie, but you can always rig
tests. 就是这么简单。
有什么错误大家指正，我晚上修改。现在不能搞了。 | A***n
发帖数: 8859 | 2 发信人: AAman (愤怒的生物博士后), 信区: Automobile
标 题: 鼓吹 Honda 安全的进来解释一下这个
发信站: BBS 未名空间站 (Wed Aug 28 12:14:32 2013, 美东)
快用百万辆死亡率解释一下09年的大车Odyssey为什么撞不过03年的最小的美国SUV。
A Parsippany mother was killed and her 12-year-old daughter was seriously
injured in a head-on accident in upstate New York on Sunday.
Kim Lynn, 41, was killed after her 2009 Honda Odyssey, which was also
carrying her three daughters, was struck by a 2003 Jeep Liberty on Route 9
West in Ulster County Sunday morning at about 6 a.m., Marlborough, N.Y.
Police Chief Gerald Cocozza said.
Lynn was pronounced dead at the scene of the crash, Cocozza said.
Her girls also sustained injuries in the incident, as did the driver of the
other vehicle involved, Cocozza said.
According to the chief, Lynn's 12-year-old daughter had to be extricated
from the vehicle. She underwent surgery at Westchester Medical Center
Tuesday after breaking her arm, hip and both legs, Cocozza said.
Her condition was not known as of Tuesday afternoon.
The other two girls, 8-year-old twins, suffered minor injuries and were
treated at St. Francis Hospital in Poughkeepsie, Cocozza said.
The driver of the other vehicle, Alexander Rigo-Mendez, 21, of Poughkeepsie,
N.Y., was taken to St. Francis with non-life-threatening injuries, Cocozza
said.
The chief said Lynn, Rigo-Mendez and the girls were wearing seat belts at
the time of the crash.
Police are investigating what caused Rigo-Mendez, who was travelling
northbound on Route 9W, to cross into the southbound lanes.
Cocozza said that no charges have been filed. Police are still investigating
the crash and have not yet determined whether alcohol or speed was a factor
, Cocozza said. |
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