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# S1 - Discrete Random Variables Q - help please!

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1. Hey guys, just finishing off an S1 past paper and I came across 3 parts to the final question which I am struggling on - I think you have to make a Cumulative Dist Table but I have forgotten how to make it. Here is the Q - it is part e, f and g I am struggling with currently!
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2. (Original post by iMacJack)
Hey guys, just finishing off an S1 past paper and I came across 3 parts to the final question which I am struggling on - I think you have to make a Cumulative Dist Table but I have forgotten how to make it. Here is the Q - it is part e, f and g I am struggling with currently!
If Jesse is to win after 2 spins that means she has to get (5, 5). That is get 5 on the first spin and get 5 on the second. You know the probability of getting a 5, so getting two 5's is those two probabilities multiplied together.

Can you identify the possible combination of moves for Tom to win after 3 spins?

No cumulative distributions are required.
3. If you can't spot what Tom needs, then check this:

Spoiler:
Show
(4,4,2), (4,4,4)
4. (Original post by Zacken)
If Jesse is to win after 2 spins that means she has to get (5, 5). That is get 5 on the first spin and get 5 on the second. You know the probability of getting a 5, so getting two 5's is those two probabilities multiplied together.

Can you identify the possible combination of moves for Tom to win after 3 spins?

No cumulative distributions are required.
Would it be a 4,5 and a 1, 2,5,3, but all the possible combinations of them three? So for example, (4,5), (5,4), (2,5,3), (3,5,2) (5,3,2) etc? Or am I going wrong?

for the part a would it just be 0.2^2, then?

Thanks
5. (Original post by iMacJack)
Would it be a 4,5 and a 1, 2,5,3, but all the possible combinations of them three? So for example, (4,5), (5,4), (2,5,3), (3,5,2) (5,3,2) etc? Or am I going wrong?
Remember that Tom only wins if it is even.

for the part a would it just be 0.2^2, then?

Thanks
Yes, that's correct for part a.
6. (Original post by Zacken)
Remember that Tom only wins if it is even.

Yes, that's correct for part a.
7. (Original post by Zacken)
Remember that Tom only wins if it is even.

Yes, that's correct for part a.
Ahhh! I see, thank you!

& @ the other guy, really??....

& couldnt tom also have (5,5,2)??? I thought the total had to be even, not the individual scores
8. (Original post by iMacJack)
Ahhh! I see, thank you!

& @ the other guy, really??....

& couldnt tom also have (5,5,2)??? I thought the total had to be even, not the individual scores
No, the spinner spins, if it is even the points go to Tom, if it is odd, it goes to Jess. Then the spinner spins again, same thing, and again, same thing - then the total is whatever.
9. (Original post by Zacken)
No, the spinner spins, if it is even the points go to Tom, if it is odd, it goes to Jess. Then the spinner spins again, same thing, and again, same thing - then the total is whatever.
Oh right okay, thank you Zacken I really appreciate it mate
10. (Original post by iMacJack)
Oh right okay, thank you Zacken I really appreciate it mate
Can you do the last part now?
11. (Original post by Zacken)
Can you do the last part now?
Yeah! Thank you
12. (Original post by iMacJack)
Yeah! Thank you
Awesome!

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