maybe you could try something like "introduction to probability". Or check this site Untitled Document
Please could someone recommend me a book which might help me understand the following problem :
"A swimming pool is emptied and then filled with several hundred thousand small plastic balls. There are black balls and there are white balls. The fraction of the balls that are black is x. I then throw in a small bucket and extract twelve balls. What is the chance that at least one ball in the bucket is a black one ?"
I might have to ask myself other similar questions.
I have a few algebra texts which deal with similar but seemingly less complicated questions of the same general type, but I'm not really sure what sort of book I'm looking for.
David Morley
maybe you could try something like "introduction to probability". Or check this site Untitled Document
Hello, David!
I can help you with this problem anyway . . .
A swimming pool is emptied and then filled with several hundred thousand small plastic balls.
There are black balls and there are white balls.
The fraction of the balls that are black is .
I then throw in a small bucket and extract twelve balls.
What is the chance that at least one ball in the bucket is a black one ?
They don't tell us the exact number of balls in the swimming pool,
. . but say there are "several hundred thousand" of them.
I must assume that, for drawing a small sample (a dozen balls),
. . the probability of getting a black ball is always .
Then this is a Binomial probability.
We have: .
The opposite of "at least one black ball" is "all white balls"
. . and: .
Therefore: .