Binomial and Binomial Probability (2 Viewers)

IS200

New Member
Joined
Oct 24, 2002
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2
hi, this may sound really stupid right now, as its only like a few days till maths exam, but, i have NO idea of how to do anything related to binomial thereom and binomial porbability. could someone please explain to me how to do a few question? i'm soooooo lost..*why did i do 3U maths?*
thanx
 

spice girl

magic mirror
Joined
Aug 10, 2002
Messages
785
Binomial Formula is just this:

(a + b)^n = (nC0)a^n + (nC1)a^(n-1)*b + (nC2)a^(n-2)*b^2 + ... + (nCn)b^n

where a, b can be anything.

Binomial probability refer to cases where there are several incidents (flips of a coin, # marbles out of a bucket, etc) to be considered, each independant of previous ones (e.g. even if you happen to get 100 heads in a row, the 101th flip will still be 1/2 probability heads, and 1/2 tails). Most important is that there are only two choices (e.g. heads or tails, black or white, left or right, etc)

Example: there are 10 black counters, each labelled "2", and 5 white counters, each labelled "3", in a container.

Bob draws 4 counters (and remembers what they were), each time replacing before the next draw.

Find the probability that:
a) The sum of the numbers is 9
b) The sum of the numbers is at least 10
c) The sum of the numbers is odd.

{Hint: the total probability is 1, so you might like to express 1 = (10/15 + 5/15)^4 }
 

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