- #1
satchmo05
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Homework Statement
A set of 25 items contains 5 defective items. Items are sampled at random one at a time. What is the probability that the 3rd and 4th defectives occur at the 5th and 6th sample draws if the items are:
a.) replaced after each is drawn?
b.) not replaced after each is drawn?
Homework Equations
I s'pose I could use the binomial theorem, but in the section this problem is in - it has not been covered. I really do not know any other useful formulas.
The Attempt at a Solution
If I were to define my events, let A: chose non-defective item, and B: chose defective item. The probability, based on the first line of the problem, is P(A) = 0.8. From here, I do not know where to start.
Any helpful hints that could get me going? Thank you for all help in advance!