help on S1 qn in blue Heinmann S1 book Watch

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sainip2000
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#1
Report Thread starter 14 years ago
#1
hi, iv done most of the questions from exercise 8A(starting on pg 150) and understand the concepts, but i got to qn13 which is a past exam question, and the layout of the question is unfamiliar to me, i dont really know what it means. so i was wondering if any of you clever people could help me out on it, and go through how its done.

Heinmann Modular Mathematics (greg attwood, gill dyer, gordon skipworth)
Blue Cover with Statistics 1 written on it
Exercise 8A, pg 153, qn 13
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jazzyj
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#2
it looks different but is the same as a normal probability distribution..write it out in a table if it helps

P(X=x) = (1/2)^x means that for x=1 P=1/2, for x=2 P=(1/2)^2 i.e. 1/4, for x=3 P=1/9 and so on

Therefore, C is found by 1 minus the sum of the probabilities up to x=5, which is 1 minus 31/32 so the answer is 1/32
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Firelight
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#3
Report 14 years ago
#3
Right you use the formula provided to work out probaility when x = whatever
eg ur proability distribution table will look like
X p(x)
1 1/2 ie 1/2^1
2 1/4 ie 1/2^2
3 1/8 ie 1/2^3
4 1/16
5 1/32
6 C
To work out C we know the probability is going to add up to 1
so its 1/2 +1/4.... +c = 1
therfeore 31/32 +c = 1
Now C = 1/32
Hope that helps
i got damn s1 tomorrow and catn do probability for beans.
all the best!
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sainip2000
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#4
Report Thread starter 14 years ago
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oooohhhhhhhhhhhhhhhhhh i seeeeee! thank you so much, i understand now! lol yeh i got S1 tomoro too, and i hate probablity questions argh so annoying them little rascals!
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MJ_23
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#5
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#5
I was stuck on it aswell, thanks for asking.
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