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# Probability distribution (S1) watch

1. Hi,

Please could someone help me with this question.

Have to list the probability distribution using:

P(W=w)
= k(w-1) w = 2,3,4,5,6,7
= k(13-w) w = 8,9,10,11,12 (the formula changes from w = 8 onwards)

I realise I need to find k to do anything, but not sure how?!

Thanks
2. P(W = 2 or 3 or ... or 11 or 12) = 1.
3. (Original post by generalebriety)
P(W = 2 or 3 or ... or 11 or 12) = 1.
Don't understand that at all, sorry!
4. (Original post by Darkest Knight)
Don't understand that at all, sorry!
Ok, well, W has to take some value (either 2, 3, 4, ..., 11 or 12). It can't just not take any of those values at all, or take something weird like 50. Right? So, the probability that W takes one of those values has to add up to 1.
5. (Original post by generalebriety)
Ok, well, W has to take some value (either 2, 3, 4, ..., 11 or 12). It can't just not take any of those values at all, or take something weird like 50. Right? So, the probability that W takes one of those values has to add up to 1.
Okay yes, I get that, but I don't understand how that helps to find k? Thanks
6. anyone?
7. (Original post by Darkest Knight)
Okay yes, I get that, but I don't understand how that helps to find k? Thanks
Add up all the probabilities and set them equal to 1. You'll be able to solve for k.

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