LFD Book Forum  

Go Back   LFD Book Forum > Course Discussions > Online LFD course > Homework 2

Reply
 
Thread Tools Display Modes
  #1  
Old 10-05-2013, 06:17 PM
eychen eychen is offline
Junior Member
 
Join Date: Aug 2013
Posts: 7
Default *ANSWER* checking the answer of Q1

Dear all,

For Q1, I got nu_min around 0.375. Therefore, [d] would be the closet answer.
I feel the answer is reasonable, for the following consideration:

1. The probablity of getting no head outcomes in 10 trails is 1/1024.
2. For 1000 ten-times-thrown coins, the probability of getting no one with head count = 0 is [(1024-1)/1024]^1000 = 0.375.
3. In most cases, when there is no one with head count =0, the lowest head count is most likely to be 1.
4. Therefore, the expectation value of nu_min will be approximately 0*0.625 + 1*0.375 = 0.375.

Am I doing anything wrong? Or I misunderstood the question?
Reply With Quote
  #2  
Old 10-06-2013, 11:11 PM
yaser's Avatar
yaser yaser is offline
Caltech
 
Join Date: Aug 2009
Location: Pasadena, California, USA
Posts: 1,477
Default Re: *ANSWER* checking the answer of Q1

Quote:
Originally Posted by eychen View Post
Dear all,

For Q1, I got nu_min around 0.375. Therefore, [d] would be the closet answer.
I feel the answer is reasonable, for the following consideration:

1. The probablity of getting no head outcomes in 10 trails is 1/1024.
2. For 1000 ten-times-thrown coins, the probability of getting no one with head count = 0 is [(1024-1)/1024]^1000 = 0.375.
3. In most cases, when there is no one with head count =0, the lowest head count is most likely to be 1.
4. Therefore, the expectation value of nu_min will be approximately 0*0.625 + 1*0.375 = 0.375.

Am I doing anything wrong? Or I misunderstood the question?
Your reasoning is both nice and correct, and the problem is just technical that when you have 1 head, the corresponding \nu is in fact 0.1, not 1.
__________________
Where everyone thinks alike, no one thinks very much
Reply With Quote
  #3  
Old 10-07-2013, 12:16 PM
eychen eychen is offline
Junior Member
 
Join Date: Aug 2013
Posts: 7
Default Re: *ANSWER* checking the answer of Q1

Hi Yaser,

I see. nu is the fraction, not the number of the head count. Thank you!
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -7. The time now is 03:19 AM.


Powered by vBulletin® Version 3.8.3
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
The contents of this forum are to be used ONLY by readers of the Learning From Data book by Yaser S. Abu-Mostafa, Malik Magdon-Ismail, and Hsuan-Tien Lin, and participants in the Learning From Data MOOC by Yaser S. Abu-Mostafa. No part of these contents is to be communicated or made accessible to ANY other person or entity.