Tuesday, March 17, 2009

5:40 PM: John Frantz has entered the room.
5:49 PM: James Foudos has entered the room.
5:50 PM: James Foudos has left the room.
5:52 PM: John Beck(Ins) has entered the room.
5:52 PM: John Beck(Ins): Hi, John!
5:53 PM: James Foudos has entered the room.
5:53 PM: John Frantz: Hello
5:53 PM: John Beck(Ins): Hi, Jimmy!
5:53 PM: James Foudos: Hello, Got it working again.
5:53 PM: John Beck(Ins): Great!
5:53 PM: John Beck(Ins): S
5:53 PM: John Beck(Ins): Was it a Java problem?
5:54 PM: James Foudos: Yeah.
5:54 PM: James Foudos: After I reformatted my computer, I never installed it.
5:54 PM: James Foudos: So it wouldn't load that chat room.
5:55 PM: John Beck(Ins): The biggest problem is that we keep getting newer and better versions of Java, but they aren't compatible with WebCT/Bb
5:55 PM: James Foudos: yeah.
5:55 PM: John Beck(Ins): That's life in the fast lane.
5:56 PM: James Foudos: haha.
5:57 PM: Margaret Cannella has entered the room.
5:57 PM: John Beck(Ins): Hi, Margaret!
5:57 PM: Marcus Buckley has entered the room.
5:57 PM: Margaret Cannella: HELLO
5:57 PM: John Beck(Ins): Hi, Marcus!
5:57 PM: Marcus Buckley: Hello everyone
6:00 PM: Danielle Ryan has entered the room.
6:01 PM: John Beck(Ins): Hi, Dani!
6:01 PM: Rachel Kruger has entered the room.
6:01 PM: Danielle Ryan: Hello, Mr. Beck ! Hello, everyone!
6:01 PM: John Beck(Ins): Hi, Rachel!
6:01 PM: Rachel Kruger: evening all
6:02 PM: John Beck(Ins): Well, Class, it's that time. Let me know when you are on L7_p1, please.
6:02 PM: James Foudos: ready.
6:02 PM: Danielle Ryan: I'm there
6:02 PM: Marcus Buckley: there
6:03 PM: Rachel Kruger: there
6:03 PM: Margaret Cannella: there
6:03 PM: John Beck(Ins): Okay, let's click on Tools, then Definitions, please.
6:04 PM: John Beck(Ins): At the bottom of the page we have a formula for determining probabilities of binomial events.
6:04 PM: John Beck(Ins): p is the probability of a success and q is the probability of a failure, so p + q = 1
6:04 PM: Vanessa Holt has entered the room.
6:04 PM: Vanessa Holt has left the room.
6:04 PM: John Beck(Ins): Hi, Vanessa!
6:05 PM: John Beck(Ins): Vanessa, we're on L7_p1. We're looking at the definitions under Tools.
6:06 PM: John Beck(Ins): So if we have a binomial situation (two possible outcomes) the probability of a r success is C(n,r)p^r q^(n-r)
6:06 PM: Salina Wiggins has entered the room.
6:06 PM: John Beck(Ins): C(n,r) looks familiar
6:06 PM: John Beck(Ins): Hi, Salina. We're on L7_p1. We're looking at the Definitions under Tools.
6:06 PM: Salina Wiggins: ok
6:06 PM: John Beck(Ins): We can use our calculator to determine p^r
6:07 PM: John Beck(Ins): And we can use our calculator to determine q^(n-r)
6:07 PM: John Beck(Ins): Let's click on "hide 'em" please.
6:07 PM: John Beck(Ins): Go to page 2, please.
6:08 PM: John Beck(Ins): I've plugged 10 for n, the number of trials.
6:08 PM: John Beck(Ins): I've plugged 2 for r, the number of success.
6:08 PM: John Beck(Ins): I've plugged .3 for p
6:08 PM: John Beck(Ins): I've plugged .7 for q
6:08 PM: John Beck(Ins): And finally, I've plugged 8 for n - r
6:09 PM: John Beck(Ins): So far so good?
6:09 PM: James Foudos: yes
6:09 PM: Rachel Kruger: yes
6:10 PM: Danielle Ryan: yes
6:10 PM: John Beck(Ins): Hmmmm. Only 3 of you are following me?
6:10 PM: Margaret Cannella: yes i am following you
6:10 PM: Marcus Buckley: yes
6:10 PM: John Beck(Ins): Okay, let's go to page 3, please.
6:10 PM: Salina Wiggins: i'm following
6:11 PM: John Beck(Ins): C(10,2) = 45
6:11 PM: John Beck(Ins): .3(.3) = .09
6:11 PM: John Beck(Ins): And finally, .7^8 is .06 when rounded off to 2 decimal places.
6:12 PM: John Beck(Ins): I actually got .05764801 when I used my calculator.
6:12 PM: John Beck(Ins): Go to page 4, please.
6:13 PM: John Beck(Ins): By the way, we cold have used a tree diagram with 10 branches to get the same answer.
6:13 PM: John Beck(Ins): I think you might want to use this formula instead of that tree diagram approach.
6:13 PM: John Beck(Ins): Go to page 5, please.
6:14 PM: John Beck(Ins): Hmmm. At least 2 sales could be 2 sales or 3 sales or 4 sales .... or 10 sales.
6:14 PM: John Beck(Ins): Or....
6:14 PM: John Beck(Ins): We could count indirectly!
6:14 PM: John Beck(Ins): Go to page 6, please.
6:15 PM: John Beck(Ins): The sum of all the probabilities is equal to 1.
6:16 PM: John Beck(Ins): So P(at least 2) is 1 minus P(0) minus P(1)
6:16 PM: John Beck(Ins): Okay?
6:16 PM: James Foudos: yeah
6:16 PM: Danielle Ryan: ok
6:16 PM: James Foudos: makes more sense than e, haha
6:16 PM: John Beck(Ins): lol
6:16 PM: John Beck(Ins): Go to page 7, please.
6:17 PM: John Beck(Ins): Go to page 8, please.
6:17 PM: Rachel Kruger: ok
6:17 PM: John Beck(Ins): Go to page 9, please.
6:17 PM: John Beck(Ins): Go to page 10, please.
6:17 PM: John Beck(Ins): Counting indirectly is a powerful tool.
6:18 PM: John Beck(Ins): Go to page 11, please.
6:18 PM: John Beck(Ins): So on 55 different days nobody was absent
6:18 PM: John Beck(Ins): On 38 days there was exactly one student absent.
6:18 PM: John Beck(Ins): etc.
6:18 PM: John Beck(Ins): Go to page 12,please.
6:19 PM: John Beck(Ins): Let's click on Tools, then Definitions, please.
6:19 PM: John Beck(Ins): At the top of the page we have a procedure for determining the EXPECTED VALUE of an event.
6:20 PM: John Beck(Ins): To make a long story short, to find the expected value, we multiply the probability of an outcome by the reward for that outcome. We do that for all the possible outcomes and then we add.
6:20 PM: John Beck(Ins): So P(E1) is the probability of event 1
6:20 PM: John Beck(Ins): R1 is the reward for event 1
6:21 PM: John Beck(Ins): etc.
6:21 PM: John Beck(Ins): Do this for all the outcomes and then add.
6:21 PM: John Beck(Ins): Let's click on "Hide 'em" please.
6:21 PM: John Beck(Ins): GO to page 13, please.
6:21 PM: John Beck(Ins): Go to page 14, please.
6:22 PM: Rachel Kruger: mr beck why do u only go to r4
6:22 PM: John Beck(Ins): According to her data, there are only 4 possible outcomes.
6:22 PM: Rachel Kruger: because number of absences?
6:22 PM: Rachel Kruger: ok thanks
6:22 PM: John Beck(Ins): Either 0 were absent or 1 was absent or 2 were absent or 3 were absent.
6:23 PM: Rachel Kruger: got it
6:23 PM: John Beck(Ins): P(0 absences) = .55 and the reward for nobody being absent is 0 so we multiply
6:23 PM: John Beck(Ins): etc.
6:23 PM: John Beck(Ins): Go to page 15,please.
6:24 PM: John Beck(Ins): Go to page 16, please.
6:24 PM: John Beck(Ins): So on any given day Ms. Beck expects .54 students to be absent.
6:24 PM: John Beck(Ins): Will there ever be a day when .54 students are absent?
6:25 PM: James Foudos: no
6:25 PM: Salina Wiggins: no
6:25 PM: John Beck(Ins): RIGHT
6:25 PM: John Beck(Ins): Okay, let's go to page 17, please.
6:25 PM: John Beck(Ins): Go to page 18, please.
6:26 PM: John Beck(Ins): There are two possible outcomes -- either you win or you lose.
6:26 PM: John Beck(Ins): Why is P(win) = 1/64?
6:26 PM: John Beck(Ins): n1 is the possible outcomes when they draw the first number.
6:27 PM: John Beck(Ins): n2 is the possible outcomes when they draw the second number.
6:27 PM: John Beck(Ins): n3 is the possible outcome when they draw the 3rd number.
6:27 PM: John Beck(Ins): There are 4 balls in each urn, so we have 4 x 4 x 4 = 64 possible outcomes.
6:28 PM: John Beck(Ins): If you buy one ticket, P(win) = 1/64
6:28 PM: John Beck(Ins): Okay
6:28 PM: James Foudos: got it
6:28 PM: Salina Wiggins: ok
6:28 PM: Rachel Kruger: ok
6:28 PM: Danielle Ryan: got it
6:28 PM: John Beck(Ins): Okay, let's go to page 19, please.
6:29 PM: John Beck(Ins): Suppose you buy 1 ticket for $1.00
6:29 PM: John Beck(Ins): Now let's suppose you win. They give you $50.00, but one of those dollars was yours so you only win $49.00
6:29 PM: John Beck(Ins): Okay?
6:29 PM: James Foudos: yup
6:30 PM: Rachel Kruger: ok
6:30 PM: Danielle Ryan: yes
6:30 PM: Marcus Buckley: ok
6:30 PM: John Beck(Ins): Go to page 20, please.
6:30 PM: John Beck(Ins): To find the expected value, we multiply the probability of an outcome by the reward for that outcome.
6:30 PM: John Beck(Ins): Go to page 21, please.
6:30 PM: Rachel Kruger: confused again why only to r2
6:31 PM: John Beck(Ins): Only two possible outcomes -- win or lose.
6:31 PM: Rachel Kruger: ok....
6:31 PM: John Beck(Ins): Go to page 22, please.
6:31 PM: John Beck(Ins): A little arithmetic.
6:32 PM: John Beck(Ins): Go to page 23, please.
6:32 PM: Deborah Poling has entered the room.
6:32 PM: John Beck(Ins): So on the average, each person who plays will lose 22 cents.
6:32 PM: John Beck(Ins): Hi, Deborah!
6:32 PM: John Beck(Ins): Deborah, we are on l7_p23
6:32 PM: Deborah Poling: hello ok
6:33 PM: John Beck(Ins): No once again, nobody loses exactly 22 cents.
6:33 PM: John Beck(Ins): You either win $49.00 or you lose $1.00
6:33 PM: John Beck(Ins): But the city of Birkbeck expects to gain 22 cents from each person who plays the pick 3.
6:34 PM: John Beck(Ins): By the way, what is the expected value for the pick 3 in Maryland?
6:34 PM: John Beck(Ins): Minus 50 cents.
6:34 PM: James Foudos: .0000000000001
6:34 PM: James Foudos: that's why I stopped playing
6:34 PM: John Beck(Ins): For each person who bets a dollar, the state of Maryland expects to keep 50 cents.
6:35 PM: John Beck(Ins): All states use a lottery to generate money. Thus the payoffs favor the states.

6:35 PM: John Beck(Ins): The expected value of a “fair” game is zero. Nobody has an advantage.
6:36 PM: John Beck(Ins): By the way, insurance companies use a much more complicated version of this formula when establishing insurance rates.
6:36 PM: John Beck(Ins): Once again, they are in the business to make a profit, so they get to keep most of the money.
6:37 PM: John Beck(Ins): Every once in a while they'll lose a bunch, but then they'll just raise the rates or they might pull out of a market if they can't predict it.
6:37 PM: John Beck(Ins): Okay, Class, that's it for tonight
6:37 PM: John Beck(Ins): Guess what? ---- You're ready for Test 2!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6:37 PM: Deborah Poling: ok
6:37 PM: James Foudos: Can't Wait!
6:37 PM: John Beck(Ins): Test 2 covers Ch 5, 6, and 7.
6:37 PM: James Foudos: Alright, Thank you.
6:37 PM: John Beck(Ins): You would be well advised to go back and review Ch 1, 2, 3, and 4
6:38 PM: Salina Wiggins: ok good night
6:38 PM: John Beck(Ins): Especially Ch 3.
6:38 PM: John Beck(Ins): The deadline for Test 2 is 4/4/09
6:38 PM: John Beck(Ins): That's the last Saturday before Easter break.
6:38 PM: John Beck(Ins): Any questions?
6:38 PM: Salina Wiggins: no
6:38 PM: Deborah Poling: no
6:39 PM: Rachel Kruger: no thanks good night
6:39 PM: Salina Wiggins has left the room.
6:39 PM: John Beck(Ins): G'night!
6:39 PM: Danielle Ryan: Ok, thanks. Good night everyone. No questions, yet.
6:39 PM: James Foudos has left the room.
6:39 PM: Danielle Ryan has left the room.
6:39 PM: Margaret Cannella has left the room.
6:39 PM: Rachel Kruger has left the room.
6:39 PM: Deborah Poling has left the room.
6:39 PM: Marcus Buckley has left the room.
6:39 PM: John Frantz has left the room.
6:39 PM: John Beck(Ins) has left the room.
6:41 PM: Toyia Haines has entered the room.
6:42 PM: Toyia Haines has left the room.