l*****y
发帖数: 317 | 1 1. Consider a deck of cards sorting from 1 to n. Drop the 1st one, retain
the 2nd one, and drop the 3rd one and retain the 4th one... by keep doing so
, what is the final card in your hand?
2. x and y have a joint normal distribution of N(mu_xy, sigma_xy). Given y
also satisfies a normal distribution of N(mu_y, sigma_y), what is the
conditional pdf of x? (make whatever assumtion you believe necessary on this
one. I wasn't so sure of the problem.)
ps: With these two problems, I would discreetly show my deep condolence and
respect to those who devoted themselves to the independence of the United
States of America. ^_^ | r*******y
发帖数: 1081 | 2 1. if n = 2^k, it is the last one left in the hand
so
this
and
【在 l*****y 的大作中提到】
: 1. Consider a deck of cards sorting from 1 to n. Drop the 1st one, retain
: the 2nd one, and drop the 3rd one and retain the 4th one... by keep doing so
: , what is the final card in your hand?
: 2. x and y have a joint normal distribution of N(mu_xy, sigma_xy). Given y
: also satisfies a normal distribution of N(mu_y, sigma_y), what is the
: conditional pdf of x? (make whatever assumtion you believe necessary on this
: one. I wasn't so sure of the problem.)
: ps: With these two problems, I would discreetly show my deep condolence and
: respect to those who devoted themselves to the independence of the United
: States of America. ^_^
| C*O
发帖数: 389 | 3 1st.
第一轮 能被2整除留下
第二轮 2,4,6,8,10,12,14,16,18,20....
留下4,8,12,16,20
剔除2,6,10,14,18
能被4整除的才留下，
第k轮
能被2^k整除才能留下 | C*O
发帖数: 389 | | m********l
发帖数: 4394 | 5 really?
what if n is odd number?
【在 C*O 的大作中提到】
: 1st.
: 第一轮 能被2整除留下
: 第二轮 2,4,6,8,10,12,14,16,18,20....
: 留下4,8,12,16,20
: 剔除2,6,10,14,18
: 能被4整除的才留下，
: 第k轮
: 能被2^k整除才能留下
| s*******0
发帖数: 3461 | 6 如果是奇数的话 那么应该是最后一张前面的一张留下
因为第一轮之后就等同是偶数的情况了
因为 如果是偶数的话 那么第一轮会删除偶数个数 所以还剩下偶数
如果是奇数的话 那么第一轮会删除奇数个数 所以还是剩下偶数
以此类推了 | s*******0
发帖数: 3461 | 7 同问
第二题不解意思
相关系数是什么？
如果是独立的话 貌似不用做吧
【在 C*O 的大作中提到】
: 第2个问题好奇怪 不明白
| j******d
发帖数: 3 | 8 错了。应该是2的最高次幂的数留下。
比如1-7，第一轮剩下246，最后剩下4=2^2，而不是6。
【在 s*******0 的大作中提到】
: 如果是奇数的话 那么应该是最后一张前面的一张留下
: 因为第一轮之后就等同是偶数的情况了
: 因为 如果是偶数的话 那么第一轮会删除偶数个数 所以还剩下偶数
: 如果是奇数的话 那么第一轮会删除奇数个数 所以还是剩下偶数
: 以此类推了
| d**t
发帖数: 183 | 9 1. 2^k <= n < 2^(k+1)
Solve for k . Last card is 2^k.
so
this
and
【在 l*****y 的大作中提到】
: 1. Consider a deck of cards sorting from 1 to n. Drop the 1st one, retain
: the 2nd one, and drop the 3rd one and retain the 4th one... by keep doing so
: , what is the final card in your hand?
: 2. x and y have a joint normal distribution of N(mu_xy, sigma_xy). Given y
: also satisfies a normal distribution of N(mu_y, sigma_y), what is the
: conditional pdf of x? (make whatever assumtion you believe necessary on this
: one. I wasn't so sure of the problem.)
: ps: With these two problems, I would discreetly show my deep condolence and
: respect to those who devoted themselves to the independence of the United
: States of America. ^_^
| r********n
发帖数: 7441 | 10 i think this is correct
【在 d**t 的大作中提到】
: 1. 2^k <= n < 2^(k+1)
: Solve for k . Last card is 2^k.
:
: so
: this
: and
| r********n
发帖数: 7441 | 11 2.
X|Y=y: ~ N(mu_x + sig_xy *(y-mu_y)/sig_yy, sig_xx - sig_xy^2/sig_yy)
y is one observation of Y
so
this
and
【在 l*****y 的大作中提到】
: 1. Consider a deck of cards sorting from 1 to n. Drop the 1st one, retain
: the 2nd one, and drop the 3rd one and retain the 4th one... by keep doing so
: , what is the final card in your hand?
: 2. x and y have a joint normal distribution of N(mu_xy, sigma_xy). Given y
: also satisfies a normal distribution of N(mu_y, sigma_y), what is the
: conditional pdf of x? (make whatever assumtion you believe necessary on this
: one. I wasn't so sure of the problem.)
: ps: With these two problems, I would discreetly show my deep condolence and
: respect to those who devoted themselves to the independence of the United
: States of America. ^_^
| s*******0
发帖数: 3461 | 12 对 疏忽了
感谢 呵呵
【在 j******d 的大作中提到】
: 错了。应该是2的最高次幂的数留下。
: 比如1-7，第一轮剩下246，最后剩下4=2^2，而不是6。
|
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