Monday, 17 September 2012

Probability Group Activity - Group 3

Mini Task 4:

(a) Flipping a coin and getting heads, then flipping it again and getting tails

Ans: Independent.  Flipping heads the first time does not mean that the coin will be more/less likely to land tails the second time. The chances are still 1/2.

(b) Rolling doubles with two dice, then rolling doubles again.

Ans: Independant. Rolling doubles the first time does not make it more/less likely that a double will be rolled a second time. The dice cannot "remember" its previous result and change the next result.

(c) Drawing (and removing) two aces from a normal deck cards, then drawing kings.

Ans: Dependant. After removing the 2 aces, there are less cards in the deck, so the deck "remembers" that 2 aces are already picked, so it is more likely that a king will be picked.

(d) Drawing (and removing) a red ball initially containing two red balls and three white balls, then drawing a white ball.

Ans: Dependent. After removing the first red ball, there are less balls in the bag, so there is a higher chance of picking a white ball.

Mini Task 5:

(a) 13/100 x 8/100 = 13/1250

(b) 1/6 x 1/6 = 1/36

(c) 1/52 x 1/52 = 1/2704

(d) 1/100 x 1/100 = 1/10000

Example 13

P(Getting heads 3 times in 3 tosses)
= 1/2 x 1/2 x 1/2
= 1/8


13 comments:

  1. They could have written P(x)= answer for mini task 5, so that its clear what is the probability for.

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  2. Mini Task 4 part b) One can only roll doubles using two dice, does that make them dependent?

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  3. Chin Wai Kit9/18/2012 10:32 am

    Very Clear, but for example three, if they had posted the question, it would have been better

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  4. It is very clear and well done. Maybe define what independent and dependent events are?

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  5. @shiying, weather or not the 2 dice will show the same number (making it a double) is dependent as weather or not we get a double on the second throw is dependent on the first throw.. But the example is talking about the event (rolling a double) happening twice. If we roll a double once, it does not affect weather we are more likely to roll a double

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  6. Very in-depth but should include a summary of what independent events are

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  7. Needs some Diagrams or photo but well explained

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  8. Very clear explanation however adding a question might have been better

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  9. For Mini task 4, they can describe what is the difference between independent and dependent events so that it will be easier to understandt mini task 4.

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  10. Diagrams or tables would help in the understanding

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  11. This is a very clear and elaborate guide. However, it would have been better if there were pictures to help the viewer visualise the question better.

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  12. Diagrams or photos would make the explanation clearer.

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  13. Along with some pictures, I think that it would be better to establish what 'dependent' and 'independent' events are before going on to provide examples to further explain your point.

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