Friday, September 10, 2010

Math Agenda

  1. Conditional Probability
  2. Probability Trees
  3. Homework Assign.
  4. Question

Conditional Probability
Ex. What is the probability of choosing a green and then a purple without replacing the green?

2 red
4 green
5 purple
Total of 11

Choosing a green - 4/11

Choosing a purple without replacing the green - 5/10 The total has been changed from 11 to 10 because the green was not replaced
Conditional probability requires to multiply

Multiply 4/11 times 5/10
= 20/110

Simplify 20/110 = 2/11


Answer: 2/11




Probability Trees
Ex:

  • If it is raining, Johnny will drive
  • Johnny drives 40% of the time when it is no raining
  • It rains 15% of the time

To make it simplier use decimals

So if 15% of the time it rains then 85% of the time is dry
From that 85% of dry weather, Johnny drives 40% of the time while the other 60% he walks
15% of the time its rainy and Johnny drives 100% of the rainy days


Answer:
---->.40 (40%) drives
Conditional: .85 x .40 ---> .34
-->.85 (85%) dry weather
Conditional: .85 x .60 ---> .51
---->.60 (60%) walks
---->1.00 (100%) rains
Conditional: .15 x 1.00 --->.15
-->.15 (15%) drive
Conditional: .15 x 0 ---> 0
----> 0 others
Total - 1.00 (100%)

Homework Assign.
Ready for class Monday
Monday's Bellringer: Probability Trees


Question
1. What is the probability of choosing a green m&m?
2. What is the probability of choosing a red m&m and then a Yellow m&m?
4 colored m&m's:
8 yellow
10 red
5 blue
2 green

11 comments:

  1. Good job Monse,

    We have to do the questions...hmmm.

    1) 2/25

    2) 2/15

    ReplyDelete
  2. I believe that the answers for number 1& 2 are:
    1)2/25

    2)10/25= 2/5 red
    8/24= 1/3 yellow
    2/5 * 1/3 = 2/15
    :)

    ReplyDelete
  3. Nice Monse....this is cool . I believe i that i may know the answers...

    Okay, so number 1.

    there are two green m&ms and a total (8+10+5+2) = 25

    So the answer is 2/25.

    Number 2.

    10/25 m&ms are red. and then 8/24. once you reduce and multiply you get 2/15.

    ReplyDelete
  4. k uumm number one i think is
    1) 2/25
    and for number 2 the answer is
    2) 2/15
    after 10/25 is reduce and multiplied by 8/24 when reduced it all comes out to 2/15

    ReplyDelete
  5. Agree with lisette and abi, NICE MONSE!

    and i agree with the other answers.

    1 is 2/25 because there are two green and 25 total

    and 2 is 2/15 because choosing the red is a 10/25 probability and for the yellow is 8/24, so multiplied and reduced is 2/15 (:

    ReplyDelete
  6. Wonderful Job Monse! :)

    1) The probability of choosing a green m&m is 2/25
    2) red= 10/25 and yellow= 8/24
    when you multiply these two fractions above, you get 80/600. When you reduce 80/600, you get 2/15.
    Therefore, the answer is 2/15

    See you tomorrow guys!

    ReplyDelete
  7. Hi i forgot we actually have to answer these questions

    1. 2green out of 25 total = 2/25
    2. 10red out of 25 = 2/5
    then 8yellow out of 24 = 1/3
    2/5 * 1/3 = 2/15

    ReplyDelete
  8. Thanks Monse! Good job!!

    I Finally Get this.. : ) lol

    1)Probability for green M&M is 2/15.

    2)Probability for choosing red m&m is 10/25 then Yellow is 8/24 because you don't count the red because you took them out. SO multiply 10/25 x 8/24= 2/15.

    ReplyDelete
  9. hey good job monse
    uum okay for number one you can see that there are two green m&ms so the probablity is 2/25. Since there are 25 m&ms all together.
    for
    2. you know that there are 10 red out of 25. so you have 10/25 X 8/24 since there are 8 yellow out of the 24 left over after havinf taken out one red m&m.
    final answers:
    1).2/25
    2).2/15
    :)

    ReplyDelete
  10. Good job monse.
    1)2/25
    2) 2/15

    this actually helped me cause i really didnt hear everything in class. thankz monse

    ReplyDelete
  11. 1. 2/25
    2. 10/25*8/24=80/600=4/30=2/15

    ReplyDelete