L******k 发帖数: 33825 | 1 A guy throws a fair six-sided die five times.
what is the probability that the number showing on each throw is higher than
the one that was showing on the previous throw. |
T********e 发帖数: 8631 | |
e*********n 发帖数: 4599 | 3 50% ?
than
【在 L******k 的大作中提到】![](/moin_static193/solenoid/img/up.png) : A guy throws a fair six-sided die five times. : what is the probability that the number showing on each throw is higher than : the one that was showing on the previous throw.
|
d*j 发帖数: 13780 | 4 total possible outcome: 5*6
each throw is higher than the previous :
1 2 3 4 5
1 2 4 5 6
1 3 4 5 6
2 3 4 5 6
so probability = 4/30
any general solution ? |
e*********n 发帖数: 4599 | 5 没有这么复杂的, 想弯了。。。
【在 d*j 的大作中提到】![](/moin_static193/solenoid/img/up.png) : total possible outcome: 5*6 : each throw is higher than the previous : : 1 2 3 4 5 : 1 2 4 5 6 : 1 3 4 5 6 : 2 3 4 5 6 : so probability = 4/30 : any general solution ?
|
d***s 发帖数: 7683 | 6 和尚你不学数学的么? 不过美国理工科本科生不会算这种题也很普遍. |
t*******y 发帖数: 11968 | 7
daj...
【在 d*j 的大作中提到】![](/moin_static193/solenoid/img/up.png) : total possible outcome: 5*6 : each throw is higher than the previous : : 1 2 3 4 5 : 1 2 4 5 6 : 1 3 4 5 6 : 2 3 4 5 6 : so probability = 4/30 : any general solution ?
|
L******k 发帖数: 33825 | 8 thanks!
【在 d*j 的大作中提到】![](/moin_static193/solenoid/img/up.png) : total possible outcome: 5*6 : each throw is higher than the previous : : 1 2 3 4 5 : 1 2 4 5 6 : 1 3 4 5 6 : 2 3 4 5 6 : so probability = 4/30 : any general solution ?
|
L******k 发帖数: 33825 | 9 很普遍!
I know I am not good at it! :)
【在 d***s 的大作中提到】![](/moin_static193/solenoid/img/up.png) : 和尚你不学数学的么? 不过美国理工科本科生不会算这种题也很普遍.
|
t*******y 发帖数: 11968 | 10
4除6的5次方
【在 L******k 的大作中提到】![](/moin_static193/solenoid/img/up.png) : 很普遍! : I know I am not good at it! :)
|
|
|
t*******y 发帖数: 11968 | 11
美国本科也学概率的
【在 d***s 的大作中提到】![](/moin_static193/solenoid/img/up.png) : 和尚你不学数学的么? 不过美国理工科本科生不会算这种题也很普遍.
|
d*j 发帖数: 13780 | 12 yeah, hehe
my bad
any general way to get the 4 ?
【在 t*******y 的大作中提到】![](/moin_static193/solenoid/img/up.png) : : 美国本科也学概率的
|
d***s 发帖数: 7683 | 13 12345
12346
12356
12456
&
13456
23456
【在 t*******y 的大作中提到】![](/moin_static193/solenoid/img/up.png) : : 美国本科也学概率的
|
d***s 发帖数: 7683 | 14 我知道. 但是学了概率并且得了A/B的大批人还是不会做这种题.
【在 t*******y 的大作中提到】![](/moin_static193/solenoid/img/up.png) : : 美国本科也学概率的
|
c********e 发帖数: 6158 | 15 6除(6的5次方)
6 possible outcomes:
12345
12346
12356
12456
13456
23456
【在 t*******y 的大作中提到】![](/moin_static193/solenoid/img/up.png) : : 美国本科也学概率的
|
j*a 发帖数: 14423 | 16 >>> 6**5/6
1296
【在 c********e 的大作中提到】![](/moin_static193/solenoid/img/up.png) : 6除(6的5次方) : 6 possible outcomes: : 12345 : 12346 : 12356 : 12456 : 13456 : 23456
|
d*j 发帖数: 13780 | 17 got a general solution:
each throw is higher than the previous :
1 2 3 4 5 6
5 throws, so randomly pick one from the above list, you get what you want,
6 ways
5 throws -- number of possible outcomes are 6*6*6*6*6
so probability is 1/6^4 |
t*******y 发帖数: 11968 | 18
推广到N面筛子和丢M次呢?
【在 d*j 的大作中提到】![](/moin_static193/solenoid/img/up.png) : got a general solution: : each throw is higher than the previous : : 1 2 3 4 5 6 : 5 throws, so randomly pick one from the above list, you get what you want, : 6 ways : 5 throws -- number of possible outcomes are 6*6*6*6*6 : so probability is 1/6^4
|
d*j 发帖数: 13780 | 19 assume M
select M out of N / N^M |
t*******y 发帖数: 11968 | 20
确信吗? M和N相差多于1的时候, 也适用?
【在 d*j 的大作中提到】![](/moin_static193/solenoid/img/up.png) : assume M: select M out of N / N^M
|
|
|
d*j 发帖数: 13780 | 21 should be working ba ...
no time le, need to go home
hehe |
c********e 发帖数: 6158 | 22 (N!/M!)/N^M
【在 t*******y 的大作中提到】![](/moin_static193/solenoid/img/up.png) : : 确信吗? M和N相差多于1的时候, 也适用?
|
L******k 发帖数: 33825 | |
L******k 发帖数: 33825 | 24 Thanks all of you!!
I submitted this take home exam in the morning!!
And my professor posted the final grade on Blackboard, I got A+~~~
Thanks, love you all.
Monk |
i**********o 发帖数: 5993 | 25 这算作弊吧?
【在 L******k 的大作中提到】![](/moin_static193/solenoid/img/up.png) : Thanks all of you!! : I submitted this take home exam in the morning!! : And my professor posted the final grade on Blackboard, I got A+~~~ : Thanks, love you all. : Monk
|
L******k 发帖数: 33825 | 26 nope!!
Professor said we could work in groups, ask google, ask friends to help!!
but we just need to write up our own solutions sets.
大白 I only asked this one question! lol
【在 i**********o 的大作中提到】![](/moin_static193/solenoid/img/up.png) : 这算作弊吧?
|
y**s 发帖数: 6809 | 27 C_{6}^{N}/6^N, N = #throws
because from every set of N numbers as long as they are all distinct you can
get an unique strictly increasing array. the problem then is reduced to the
probability of getting such sets. sorry heshang i'm late but
congratulations!!
than
【在 L******k 的大作中提到】![](/moin_static193/solenoid/img/up.png) : A guy throws a fair six-sided die five times. : what is the probability that the number showing on each throw is higher than : the one that was showing on the previous throw.
|
L******k 发帖数: 33825 | 28 Thanks!!
I am sure I will get more interesting questions form NYU later!
can
the
【在 y**s 的大作中提到】![](/moin_static193/solenoid/img/up.png) : C_{6}^{N}/6^N, N = #throws : because from every set of N numbers as long as they are all distinct you can : get an unique strictly increasing array. the problem then is reduced to the : probability of getting such sets. sorry heshang i'm late but : congratulations!! : : than
|
i**********o 发帖数: 5993 | 29 下回这种问题。我给你写程序。反正上班闲着。
【在 L******k 的大作中提到】![](/moin_static193/solenoid/img/up.png) : nope!! : Professor said we could work in groups, ask google, ask friends to help!! : but we just need to write up our own solutions sets. : 大白 I only asked this one question! lol
|
y**s 发帖数: 6809 | 30 let me know if there's anything interesting on your curriculum! i will have
plenty of time and would be glad to audit!
【在 L******k 的大作中提到】![](/moin_static193/solenoid/img/up.png) : Thanks!! : I am sure I will get more interesting questions form NYU later! : : can : the
|
|
|
L******k 发帖数: 33825 | 31 Thanks~!! I will let you know!!
The problem is we have to think how to teach it to our students and let them
understand!!
This summer I will take course in Special Education!!
have
【在 y**s 的大作中提到】![](/moin_static193/solenoid/img/up.png) : let me know if there's anything interesting on your curriculum! i will have : plenty of time and would be glad to audit!
|
y**s 发帖数: 6809 | 32 汗.我现在就想找人监督我把高等数学大三册好好念下来...
them
【在 L******k 的大作中提到】![](/moin_static193/solenoid/img/up.png) : Thanks~!! I will let you know!! : The problem is we have to think how to teach it to our students and let them : understand!! : This summer I will take course in Special Education!! : : have
|