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spcs:summer2014:day_10 [2014/07/04 08:35]
ffpaladin [SPCS - Day 10]
spcs:summer2014:day_10 [2015/07/05 16:35]
ffpaladin [Assignment]
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 +
 +====== SPCS - Day 10 ======
 +
 +Free Seating Friday!
 +
 +Afternoon Groups: Work individually or with a group if you'd prefer, but please ask for help, if you need it. Please help each other out!
 +
 +I'm doing one-on-one meetings with each of you on Monday!
 +
 +
 +
 +===== Topics =====
 +  * Monty Hall
 +  * Bayes
 +  * https://​www.youtube.com/​watch?​v=TYIh4MkcfJA
 +  * Arduino
 +  * https://​www.youtube.com/​watch?​v=UoBUXOOdLXY
 +  * Boolean Algebra
 +  * Logic Gates: https://​dl.dropboxusercontent.com/​u/​3235343/​Teaching/​Logicly.swf ​
 +  * http://​www.skot9000.com/​ttl/​datasheets/​8.pdf
 +  * http://​www.skot9000.com/​ttl/​
 +  * http://​www.ee.calpoly.edu/​media/​uploads/​resources/​KarnaughExplorer_1.html
 +  * Circuits
 +  * https://​www.khanacademy.org/​science/​physics/​electricity-and-magnetism/​v/​circuits--part-1
 +  * http://​dlnmh9ip6v2uc.cloudfront.net/​datasheets/​Kits/​SFE03-0012-SIK.Guide-300dpi-01.pdf
 +
 +
 +
 +===== Assignment =====
 +
 +Math Probability Problem (Optional Challenge)
 +
 +There is an urn containing three balls. Each ball is either red or blue, and two balls have the same color. So, there are two possibities:​ either two balls are red and one is blue (the “majority-red case”) or two balls are blue and one is red (the “majority-blue” case). The probability of both cases is the same, i.e., 50%. 
 +John is allowed to draw a random ball from the urn, look at it, and put it back. Then, he has to make a guess as to whether he thinks the urn is majority-blue or majority-red. Let’s say that John has drawn a red ball. It seems 
 +natural that John should guess that the urn is probably majority-red. We now ask you to confirm this is a good 
 +guess, using Bayes’ rule. 
 +
 +Let “MajRed” be the event that the urn is majority-red. So, “not MajRed” is the event that the urn is not majorityred,​ which means that the urn is majority-blue. Let “RedBall” be the event that John picked a red ball. We are interested in the probability P(MajRed|RedBall) that the urn is majority-red given that John has picked a red ball.
 +
 +  * (a) What is the prior probability P(MajRed) according to the above description?​
 +  * (b) What is the conditional probability P(RedBall | MajRed)?
 +  * (c) What is the conditional probability P(RedBall | not MajRed)?
 +  * (d) Finally, using Bayes’ rule and other rules, what is the conditional probability P(MajRed | RedBall)?
 +
 +John decided to declare that he thinks the urn is majority-red. Next, it’s Mary’s turn to pick a random ball from the rn, look at it, and put it back. She picks a blue ball. Now, she is in the same situation as John: she has to make a guess about the urn based on what she has seen. But, she also knows that John has seen a red ball (because otherwise he would not have said that he thinks the urn is majority red). 
 +
 +Mary is not sure what to think. On the one hand, she saw a blue ball, and therefore the urn is most likely majorityblue. On the other hand, she knows that John has picked a red ball, which suggests that the urn is majority-red. ​
 +
 +We can solve this problem again using Bayes’ rule. Let “RedThenBlue” be the event that John picked a red ball, 
 +and then Mary picked a blue ball (which is what happened). ​
 +
 +  * (e) What is the conditional probability P(MajRed | RedThenBlue)?​
 +
 +Hint: this can be computed using the same techniques as in (a)-(d).
 +
 +Answer: http://​users.soe.ucsc.edu/​~sherol/​teaching/​doku.php?​id=epgy:​ai13:​bayes_problem_solution
 +
 +===== Blog =====
 +
 +    * Projects (as usual)
 +
 +===== Arduino =====
 +
 +    * You know what to do!
 +    * Take pictures and blog it!
 +
 +Have fun! Great work, class!
 +
 +===== Feedback =====
 +
 +https://​docs.google.com/​forms/​d/​1nNvgtxwBtGiDMfe_jjx1PH8MzwJlOR7jIAaEdLZ-sZI/​viewform
/soe/sherol/.html/teaching/data/pages/spcs/summer2014/day_10.txt · Last modified: 2015/07/05 16:35 by ffpaladin