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全部话题 - 话题: tossing
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s**********n
发帖数: 2343
1
California's 8th State Assembly District - TOSS-UP
Geography: Citrus Heights, Rancho Cordova
November ballot: Ken Cooley (D) vs. Peter Tateishi (R)
Senate 2010: Fiorina 48-43
Governor 2010: Brown 50-43
President 2008: Obama 52-45
California's 61st State Assembly District - TOSS-UP
Geography: Riverside, Moreno Valley
November ballot: Bill Batey (R) vs. Jose Medina (D)
Senate 2010: Boxer 50-41
Governor 2010: Brown 53-39
President 2008: Obama 60-36
California's 66th State Assembly District - TOSS-U... 阅读全帖
b**j
发帖数: 20742
2
来自主题: Football版 - official OT rule
请注意opportunity to possess
POSTSEASON – MODIFIED SUDDEN DEATH
The modified sudden death system of determining the winner shall prevail whe
n the score is tied at the end of regulation playing time of postseason NFL
games. The system guarantees each team a possession or the opportunity to po
ssess, unless the team that receives the opening kickoff scores a touchdown
on its initial possession.
· At the end of regulation time, the Referee will immediately toss
a coin at the center of the fie... 阅读全帖
z******n
发帖数: 1223
3
来自主题: Football版 - 咳嗽灵一把年纪今天又爽到了
毕业扔帽子叫tossing,把人往水里扔啥的也可以用这个
看过回忆清华马约翰教授的文章说他鼓励学生运动,其中一项就是互相“拖尸”,旁边
注的英文是tossing
不过用到美国体育有个特殊情况,就是抛硬币叫Coin Toss
扔教练的话,平实点也就说throw the coach in the air吧
s*****h
发帖数: 44903
4
☆─────────────────────────────────────☆
dango (吃蛋糕) 于 (Tue Jan 19 13:13:17 2016, 美东) 提到:
NCAA OT规则问题在于无视特工组的价值.
NFL OT规则问题是可能有一方没有possession就输了
同时,OT规则的两大基本点是尽量公平(减少coin toss决定先后产生的胜负影响),
且尽可能速战速决(否则电视转播要来拼命)。
基于此,我老的设想是:
每队打一次2 mins drill,从kick off开始,return之后的field position作为起点。
所有规则都与常规时间的最后两分钟相同,超时或Lost possession后由对方从相应位
置开始,如果得分则kick给对手从return end处开始,也必须在2分钟内完成进攻。每
队各有3次暂停,可在攻防任何时间用。在两队都获得possession并有至少一方得分后
比赛结束,得分高者胜。每队各有一次possission且得分相同,则谁再次得分谁胜(或
者是谁得分用的play clock时间少谁胜,这条没想好哪个更合适)... 阅读全帖
ET
发帖数: 10701
5
'coz the power is generated by hip rotation.
it's not such thing called speical for me. I always tell myself," want to
hit bigger, stay easy."..
I guess the part I don't like most is about his hip rotation thing, if it's
his word.
not everyone has a natural hip rotation, if the one has not been trained by
other similar sport. Don't believe, just simply toss the golf ball to the
target, as hard as possible. natural toss it. then toss the ball using the
hip rotation. let your hand/arm for directio
c****1
发帖数: 5654
6
congrat.s, looks like you should cont. to play icc tours to reach
1900 lah.
i even didn't see my own video.s, guess it was shot in 05, 5 years
ago, my game changed a lot:
i didn't play as aggressive as in my 30s, like to move back to
defense, like to slow down the point, play more consistently.
Serve wise, i toss less high, so more consistent, besides screw
spins, which was the main spin i started to serve high toss, i added
down spins to 2 short corners, also like backhand high toss serve
eithe
n*********4
发帖数: 83
7
Pete's serve is really one of all time best. I think that is one area he is
definitely better than Roger.( not that Roger has a bad serve) Especially on
second serve, Pete is really the best. Pete's knee bends is the lowest I
have ever seen.(tried it myself, totally screw up the timing) He also has an
unique ball toss, his left hand does not toss the ball straight up,instead,
it goes up from his right thigh area, this gives him a bigger shoulder turn
, and also this toss has a little curve, and
a*m
发帖数: 6253
8
来自主题: Tennis版 - [技术讨论帖] 发球动作分解
Your serve is good enough leh.
If any improvement, I think you need to get underneath the ball, like
overhead... Or you have to align your toss...
On frame 3, you hit the ball on the side, which is normally ok for a slice
position...
Toss a little back will help you do the kick, if your wrist is relaxed
enough...
You can try the way Pete used: let your wife call the T/W/B after your toss.
..
a**s
发帖数: 9606
9
来自主题: Tennis版 - [技术讨论帖] 发球动作分解
toss is not a problem for me. I can toss to anywhere I need.
I tried to do more pronation tonight. Here is a short video:
http://www.youtube.com
Please common ASAP. I might take it off tomorrow since ...

toss.
a*****3
发帖数: 10373
10
来自主题: Tennis版 - 太郁闷了!
从上星期三到这星期一是semifinal的time frame.对手其实在小组时已经碰过头了。
小组时,他是我week6的对手,结果这家伙头两个weeks就已经打了四场,而且都是狂胜
对手。原本是他主场,还主动联系我说可以跑到我这边来打,真是积极呀。我刚好
week2的对手没空,就答应他了。是个劳模。一打起来,原来是个战术派,什么球都跑回
来,长拉短吊,我想怪不得能赢其他对手这么多啦。可惜,他遇到的是我这个ultimate
pusher,我知道用pusher打法肯定能轻松赢他,就改打暴力好了,而且还要tanking.好
不容易能够以close的比分赢了下来。赛后,劳模说想不到如何能赢我。也就是这场比
赛的胜负,最后league playoff的no.1 seed,由他变成了我。。。
想不到冤家路窄,semifinal又碰到他了。forecast说从上周四起开始有雨。我第一时
间联络他,以为他也会象在小组赛那样积极,结果他就一拖再拖,最后我催得急,他说
这几天都有雨,就订星期一晚上吧。靠,星期一晚上不就是最后时刻吗!而且他还强调
secure court是我主场的责任。晚上的public... 阅读全帖
j**c
发帖数: 234
11
来自主题: Tennis版 - 发球成瓶颈了
a few minor stuff from video (1) timing "hitch"- ther is an obvious racket
pause in the middle air waiting for ball to drop which breaks toss-hit
rhythm and the kinetic chain. try a smooth continous swing motion and/or
lower the toss. (2) footwork bofre serve-aligh left foot 45 dgree to the
baseline instead of 0 degree to baseline which require too much twist. (3)
footwork during serve-shit weight back when tossing the ball, and shift
weight forward when striking instead of somewhere in the midd... 阅读全帖
d*g
发帖数: 16592
12
来自主题: Tennis版 - 发球已经n年没有一弹触网了
timing不好其实是toss不好,没事儿就toss,兜里揣个球,等公共汽车,排队结帐,
看电视时候,这样几个星期,toss就上一个层次,呵呵。
注意别让熟人看到,该以为咱有病了。
g*****y
发帖数: 7271
13
来自主题: Tennis版 - 还是二发练习
感觉toss太高,而且toss也不够稳定,容易导致双误。toss高是由于手上动作比较多,
swing不够简洁。
x*d
发帖数: 1696
14
来自主题: Tennis版 - 请教一二发抛球
Actually most pro toss differently, even Federer, there is no need to
disguise between 1st and 2nd. Even pro don't push for same- toss-different-
spin with their physical flexibility. Most amatuer don't have that much
flexibility.
Tossing them same only makes your 1st and 2nd alike. Either 1st is slow, or
the 2nd is too flat.
c*******7
发帖数: 465
15
来自主题: Tennis版 - 奔一发纯动作求助了
I think you bend your knees too early. It looks like you are bending your
knees while tossing the ball, which makes your tossing unstable. Try to bend
after the ball is tossed out of the hand.
z*********n
发帖数: 94654
16
来自主题: Tennis版 - usta 迟到的正式规定
COACHING: Coaching is not permitted. (No cell phones or electronic devices
allowed on court)
WARM-UP & DEFAULT: There will be a five minute warm-up period, including
practice serves.
The USTA Point Penalty System shall be used:
5:00 minutes or less - Loss of Toss + 1 game
5:01 to 10 min. - Loss of Toss + 2 games
10:01 to 15 min. - Loss of Toss + 3 games
Over 15 min. - Default
迟到0-5分钟就输一个game,10 到15分钟迟到就输三个game
十五分钟就自动算输
真严啊。。。
d******t
发帖数: 583
17
来自主题: Tennis版 - 奔:用continental grip发球
en. Good point, maybe you and Food-God are talking about
same thing, high toss...... High toss will buy time to
do full motion and pause
High toss will actually naturally make left arm straight
But timing will become more tricky
d******t
发帖数: 583
18
来自主题: Tennis版 - 奔:用continental grip发球
:) My target is not to toss as high as those WTA Russians,
I think Nadal or S-Williams's toss is a pretty good compromise,
still much higher than my current toss though.
b*********s
发帖数: 6757
19
no, you shouldn't try to feed by hitting the ball. You should stay on the
same side as him, and just toss the ball with your hand.
For what you are currently work on. Get a can, water jug or whatever, put it
on the baseline, and have you kid stand behind it, you get a basket of
balls and stand halfway between the service line and the net, just toss the
ball inside the service line and have you kid run up to hit. If he can
consistently make the shot, move the can/jug back by 1m, and do it again,
... 阅读全帖
L*********n
发帖数: 185
20

can
play
be
I like this one.
Toss Feed is very important because you can't counter punch and you have to
generate power by yourself. Without a proper technique, it's almost
impossible to hit toss fed ball w/ good power and spin.
Plus it's easy to do and every parent and do it following the video.
When I don't have a partner, I usually toss fed my self and play against a
wall:).
j**h
发帖数: 480
21
来自主题: Tennis版 - 奔Flat & Slice发球
根据发球教学视频,slice, flat serve tossing 应该偏右,topspin 偏左或居中.
你的tossing确实隐蔽性很好,所有的发球都是一个抛球位置,偏左偏后,看不出你想
发哪,
但感觉你要发topspin.这可能也是为什么我有这样的错觉,觉得你的发球都象topspin
serve,
你的tossing 位置可能比较适合你的发法,能较多的用到你的腰力,但我感觉达到相同
的power,
你的方法比传统教练教的方法费力气。
N*****7
发帖数: 1899
22
来自主题: Tennis版 - 发球练习 [录像】
是不是说左右手不同步? 我看录像是左手toss时, 右手拍子下垂了, 然后要赶着追那
个抛起来的球, 比较赶。 toss的好像有些后, 也不稳。
以后试试双手一起向上, 左手toss时不把右手放下。。
w*****g
发帖数: 615
23
来自主题: Tennis版 - 发球练习 [录像】
toss to 11 o'clock: slice wide
toss to 12 o'clock, down the T.
You are telling people what you will serve. Try to have one toss?
h******n
发帖数: 734
24
来自主题: Tennis版 - 抛球应该用几根手指?
if toss is low u gotta bend as you toss. sampras has a pretty high toss.
all personal pref.
b*********s
发帖数: 6757
25
来自主题: Tennis版 - Slice Serve 要Pronation吗?
I actually lowered my toss now. I think it's better... I can serve
relatively well during practice, but still struggle a bit in the match due
to the change, I feel rushed....
One thing about high toss is sometimes you sorta have to "wait" and when you
are nervous and tight, that "wait" time could really screw you up. I'm not
saying low toss is better, it's more about finding the optimum high for
yourself.
p*****k
发帖数: 318
26
来自主题: BrainTeaser版 - 来一个扔硬币
sorry if the "linearity" i mentioned caused confusion.
# of tosses to get "TTT"
= # of tosses to get "TTT" or "HHH", whichever appears first
+ # of tosses from either pattern to "TTT"
then take average on both sides.
the last term is 0 if "TTT" appears first; and is same as E["TTT"]
if "HHH" appears first.
a***a
发帖数: 40617
27
来自主题: E-Sports版 - 今晚有gsl2!
这jb这个zerg怎么进的64强
太jb菜了
人家光炮没封住你家,你直接cancel 2矿
然后家里蟑螂一波,出门直接去toss家
toss投资了100+150*2=400的资源
你几个小强就把toss弄死了
什么脑子啊
a***a
发帖数: 40617
28
来自主题: E-Sports版 - 我tvp完全没法了
对于你们这个级别,不会运营的,当然不imba
toss弱是弱在运营比不过,所以现在打来打去只能4BG
toss到底强弱如何,看看GSL1到3就知道了
GSL也不是邀请赛,GSL2和GSL3都是几千人打出来64强,还就那么几个toss,而且基本
都一轮男
a***a
发帖数: 40617
29
来自主题: E-Sports版 - 给力,voidray+zealot
看到没!我早说了,之前PVT那些imba战术依然有效,因为patch没变,toss也没有更好的
应对
果然就是如此
老外用了banshee一波就轻松带走toss!
toss那么好的力场,毛用都没有
c****s
发帖数: 190
30
来自主题: E-Sports版 - 前面gsl几乎所有冠亚军
他的TOSS用的很有攻击性。我发现他是唯一一个前中后期都敢和人刚正面的TOSS。大多
数TOSS一盘比赛只会和对方主力交战1,2次。
说实话,上赛季输给JINRO太特么让人匪夷所思了~
a***a
发帖数: 40617
31
来自主题: E-Sports版 - CodeS
说明toss训练不刻苦,但是有脑
前端时间TVP,各种纯光头打巨像打得toss痛不欲生
toss直接就不跟你玩巨像了
不过奶大被干了个光头,我没想到
O*******o
发帖数: 7091
32
来自主题: LeisureTime版 - 秋天,让我们一起赶集去 (转载)
【 以下文字转载自 Zhejiang 讨论区 】
发信人: wh (wh), 信区: Zhejiang
标 题: 秋天,让我们一起赶集去 (转载)
发信站: BBS 未名空间站 (Sun Nov 10 18:58:49 2013, 美东)
发信人: wh (wh), 信区: Connecticut
标 题: 秋天,让我们赶集去
发信站: BBS 未名空间站 (Sun Nov 10 18:39:49 2013, 美东)
美国各地秋天都有fair吗?新英格兰地区的土著好像都对fair有特殊的感情,我的同事
和当地朋友小时候都跟爸妈去过麻省的Big E——新英格兰最大的fair——都跟我绘声
描述农民自制的新鲜冰淇淋和苹果派、来自东北各州的特色农产品和手工艺品、来自全
世界的稀奇古怪的动物……边说边流露出儿童年代的纯真与向往,总让我觉得Big E是
比迪斯尼更淳朴贴地的童年天堂。
今年没去成Big E;在local报纸上看到当地的 fair有小猪赛跑、tractor pull、oxen
draw、horse draw、Women’s Skillet Toss等活动,既好奇又无知:pull... 阅读全帖
wh
发帖数: 141625
33
来自主题: Zhejiang版 - 秋天,让我们一起赶集去 (转载)
【 以下文字转载自 Connecticut 讨论区 】
发信人: wh (wh), 信区: Connecticut
标 题: 秋天,让我们赶集去
发信站: BBS 未名空间站 (Sun Nov 10 18:39:49 2013, 美东)
美国各地秋天都有fair吗?新英格兰地区的土著好像都对fair有特殊的感情,我的同事
和当地朋友小时候都跟爸妈去过麻省的Big E——新英格兰最大的fair——都跟我绘声
描述农民自制的新鲜冰淇淋和苹果派、来自东北各州的特色农产品和手工艺品、来自全
世界的稀奇古怪的动物……边说边流露出儿童年代的纯真与向往,总让我觉得Big E是
比迪斯尼更淳朴贴地的童年天堂。
今年没去成Big E;在local报纸上看到当地的 fair有小猪赛跑、tractor pull、oxen
draw、horse draw、Women’s Skillet Toss等活动,既好奇又无知:pull和draw是拔
河吗?Skillet Toss比谁把锅里的菜扔得最高?好奇是人类进步的动力,让我带你去解
谜——
Fair从周五黄昏开始,看和煦的落日洒在一辆辆农民从家里开来参展的老爷拖... 阅读全帖
b******k
发帖数: 1874
34
来自主题: Zhejiang版 - 秋天,让我们一起赶集去 (转载)
有啊,我家附近的几个小镇都有一年一度的大集会,但是那是以贸易为主。那个时候物
资不丰富,也没有义务小商品这样的市场,所以这样的集会是一个很好的货比三家,买
些好东西的机会。
对于小孩,大抵也是很开心的,因为会有一些配套的杂耍,小吃。不过,最多的还是人
,那是真的前胸贴后背:)我在读小学的时候每年都会跟大人去其中的一个集会,因为
刚好有一个亲戚在那边。那天就像是过节一样,现在想起来还是很“温暖的”,呵呵。
。。。。。。
现在估计是热闹依旧,不过不会有那么的拥挤了

【 以下文字转载自 Connecticut 讨论区 】
发信人: wh (wh), 信区: Connecticut
标 题: 秋天,让我们赶集去
发信站: BBS 未名空间站 (Sun Nov 10 18:39:49 2013, 美东)
美国各地秋天都有fair吗?新英格兰地区的土著好像都对fair有特殊的感情,我的同事
和当地朋友小时候都跟爸妈去过麻省的Big E——新英格兰最大的fair——都跟我绘声
描述农民自制的新鲜冰淇淋和苹果派、来自东北各州的特色农产品和手工艺品、来自全
世界的稀奇古怪的动物……边说边流露出儿童年... 阅读全帖
c*********0
发帖数: 757
35
来自主题: Mathematics版 - 急,,,求助3道概率问题
1) Prove or disprove: if two events are mutually exclusive, then the two
events are independent.
2)a coin is tossed a sequence of times, what is he probability that the
first head will occur after the fifth toss, given that it has not occurred
in the first two tosses
3) prove that for any three events ,A,B,C, each having positive probability
and with the property that P(A n B) > 0, THEN : P(A n B n C)=P(A)P(B I A)P(C
l A n B)
i***q
发帖数: 1095
36
来自主题: Mathematics版 - 弱人问个题 (转载)
【 以下文字转载自 Statistics 讨论区 】
发信人: iamwq (will), 信区: Statistics
标 题: 弱人问个题
发信站: BBS 未名空间站 (Tue Nov 17 13:38:18 2009, 美东)
Suppose that balls are tossed into b bins. Each toss is independent, and
each ball is equally likely to end up in any bin. What is the expected
number of ball tosses before at least one of the bins contains two balls?
l***e
发帖数: 13
37
来自主题: Quant版 - Quant面试问题
今天拿到了口头offer, 在quant版学习了不少东西,也希望贡献一点力量,所以把记得
的面试问题写出来。祝大家都找到满意的工作。
I got all the questions in interviews. I am trying to make all answers/hints
accurate but can not guarantee.
Brainteasers
1. a normal dice with 6 sides with numbers from 1 to 6, toss it at most
three time. After each toss, you get a number x, you can either continue or
get x dollars. What is the game worth?
2. the same rule as question 1, What would you like to pay to play the game?
3. a coin, toss a number times until you get a
B*********h
发帖数: 800
38
来自主题: Quant版 - [合集] the dice game
☆─────────────────────────────────────☆
atreeyang (随风的白杨~) 于 (Sat Dec 16 04:08:39 2006) 提到:
1. a normal dice with 6 sides with numbers from 1 to 6, toss it at most
three time. After each toss, you get a number x, you can either continue or
get x dollars. What is the game worth?
2. the same rule as question 1, What would you like to pay to play the game?
I think the game may worth 5 dollars, because you toss the dice three times
, and the probility of all the three times x<5 is 2/3 * 2/3 *
b***k
发帖数: 2673
39
来自主题: Quant版 - [合集] an interview question
☆─────────────────────────────────────☆
crystalike (New Start) 于 (Fri Sep 19 15:26:39 2008) 提到:
not sure if this is an old one.
A and B tossing a fair coin. A toss N times and B toss N+1 times. What is
the probability of B getting more heads than A.
☆─────────────────────────────────────☆
wangjuestam (penpen) 于 (Fri Sep 19 15:33:11 2008) 提到:
I think it's 1/2. My thoughts would be for the first N times, A and B should
have exactly the same expectation number of heads.
☆─────────────────
g********t
发帖数: 11
40
Is the first toss independent of the second one?
if yes, the first shall have the same probability as the second one to be
Head, which is denoted as p.
the best estimation of p based on the first Head is one!?
assuming p is a fixed probabity (number) for a coin toss.
otherwise, assuming p is uniformly distributed in (0,1), the answer is 2/3??? the second toss is Head with the same probability p, whic has mean of 1/2.
h*****a
发帖数: 52
41
1. There are some unbiased coins (equal probability of having head and tail
when tossed). Initially, all the coins are tossed. The following steps are
followed after that:
- turn all the Head up coins to Tail.
- toss all the Tail up coins.
Find the probability of finding the a coin Head up after 'n' pairs of steps,
( or to frame it differently, find the number of coins with Head up) (Hint:
think in terms of ratio)
Ideas?
o****e
发帖数: 80
42
来自主题: Quant版 - 请教2道概率题
expected toss in second question:
my solution is like this,
Markov chain
u0=0 u3=0
u1=1+0.6*u2+0.4*u0
u2=1+0.6*u3+0.4*u1 → u1=40/19 u2=35/19
so the expected toss is 40/19?
可是为什么从第二个人算,expected toss 就是 35/19?
o*p
发帖数: 77
43
来自主题: Quant版 - Jane Street Interview Questions
a little correction to problem 2,when the 5th time toss is added to one
person(A), you will find the 5th toss will have 1/2 probability to change
the result.if A is just one head less than B, when A gets head at the fifth
toss, A will win, so there has 4/5^2 probability to happen
then A wins will increase to 3/5+4/5^2=19/25.
so the total prob A wins will be 1/2*5/3+19/25*1/2=17/25.

not
i**w
发帖数: 71
44
背景:fresh physics PhD
还没offer,但年前基本上不会再折腾了。
有重复。基本上都是很标准的题。
简单的题如果人家想问倒你也是很容易的。
面试书recruiter推荐
1) Mark Joshi: "Quant Job Interviews: Questions and Answers". I have
heard very good things about this book.
2) Xinfeng Zhou, "A Practical Guide to Quantitative Finance Interviews"
个人觉得非常有用, 大部分问题都在这两本上。
算法,C++, stochastic calculus 就看比较标准的几本。
- sqrt(i)=?
- You and me roll a dice,first one gets a six wins. You roll first. what
is the probability of you winning?
- A stair of n steps. Each time you st... 阅读全帖
h**********y
发帖数: 41
45
来自主题: Quant版 - What is Var(N) in this game?
Suppose we toss a fear coin, and let N denote the number of tosses until we
get a head (including the final toss). What is E(N) and Var(N)?
I know E(N)=0.5*1+0.5*( E(N)+1 ), so E(N)=2.
Can I use this way to calculate Var(N)?
I know there is a solution in Joshi's red book, but that looks complicated,
Any other method to calculate Var(N)?
p**e
发帖数: 41
46
来自主题: Quant版 - 3个面试的小问题求解
大家好, 我有3个面试的小问题, 求解:
1, 任意选择3个点在一个圆周上, 问它们连成的三角形includes圆心的概率? (答
案是0.25, 为什么)
2,3个player玩toss a coin的游戏, 游戏规则是首先toss到head的人赢, 如果第一
个人toss了tail, then他把coin给下一个人玩, 这样循环下去一直到有人赢。 问这
三人每人的赢的概率分别是多少?(答案是 第一个人4/7 第二个人2/7 第三个人1/7
, 怎么得到的?)
3,n×n矩阵A,其对角线元素全部为1,其他元素全部为k, 求A的eigenvalue?
y*******u
发帖数: 930
47
来自主题: Quant版 - 3个面试的小问题求解
第一个 注意到圆周上任意两点均可以组成一个半圆
分别画出这2点的直径
第三点只能在这2点直径的交集内部
那么概率等于第一点和第二点之间的圆心角
所以概率是(0,1/2)
注意到是等权重的,那么概率就是1/4
第二个就是个无穷等比级数啊
级数是1/8
第一个player 就是1/2+1/16+1/64
等比级数求和 1/2/(1-1/8)=4/7
第二个的首项是1/4 求和2/7
第三个1/7

大家好, 我有3个面试的小问题, 求解:
1, 任意选择3个点在一个圆周上, 问它们连成的三角形includes圆心的概率? (答
案是0.25, 为什么)
2,3个player玩toss a coin的游戏, 游戏规则是首先toss到head的人赢, 如果第一
个人toss了tail, then他把coin给下一个人玩, 这样循环下去一直到有人赢。 问这
三人每人的赢的概率分别是多少?(答案是 第一个人4/7 第二个人2/7 第三个人1/7
, 怎么得到的?)
3,n×n矩阵A,其对角线元素全部为1,其他元素全部为k, 求A的eigenvalue?
l**********e
发帖数: 18
48
来自主题: Quant版 - 3个面试的小问题求解
不知道这样解决是否正确:
1, 任意选择3个点在一个圆周上, 问它们连成的三角形includes圆心的概率?
//include圆心的话,3个点组成的三角形中最大的角度数需要小于等于90度,而三个点
组成的三角形最大角的度数范围为0-360度,因此概率为0.25?
2,3个player玩toss a coin的游戏, 游戏规则是首先toss到head的人赢, 如果第一
个人toss了tail, then他把coin给下一个人玩, 这样循环下去一直到有人赢。 问这
三人每人的赢的概率分别是多少?
//
假设概率分别为a1,a2,a3
则第一轮概率为
0.5 0 0
0 0.5^2 0
0 0 0.5^3
后续每轮概率皆是如此,只不过需要乘以 0.5^(3n-3),其中n为轮数。
由此可得如下规律
a1=2a2=4a3
同时
a1+a2+a3=1
因此可得
a1=4/7,a2=2/7,a3=1/7
c**********e
发帖数: 2007
49
来自主题: Quant版 - 请教一个Markov Chain
对于普通的coin toss, 知道S_n,现在的score足够了。因为下次的score要么是S_n+1,
要么是S_n-1。所以,S_n是马尔可夫的。
但是对于楼主定义的coin toss,知道S_n,现在的score是不够的。你还要现在的toss
X_n才
知道下一步的状态。所以,S_n不是马尔可夫的,而(S_n,X_n)是。
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