- #1
Townsend
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There is a question in my text that list an answer in the back of the book that seems wrong to me.
It is,
"Four microprocessors are randomly selected from a lot of 100 microprocessors among which 10 are defective. Find the probability of obtaining no defective microprocessors."
There are C(100,4) ways of selecting 4 microprocessors from 100 and this is our sample space. There are 90 non-defective microprocessors and so there are C(90,4) ways to select a non-defective microprocessor. So our number of out comes of the event is C(90,4) and so the probability of the event is
P(E)=C(90,4)/C(100,4).
The answer in the back of the textbook is given as
C(90,10)/C(100,10)
This answer does not make much sense to me since we are selecting 4 things and not 10 things. Am I right or is the book right?
Thanks
It is,
"Four microprocessors are randomly selected from a lot of 100 microprocessors among which 10 are defective. Find the probability of obtaining no defective microprocessors."
There are C(100,4) ways of selecting 4 microprocessors from 100 and this is our sample space. There are 90 non-defective microprocessors and so there are C(90,4) ways to select a non-defective microprocessor. So our number of out comes of the event is C(90,4) and so the probability of the event is
P(E)=C(90,4)/C(100,4).
The answer in the back of the textbook is given as
C(90,10)/C(100,10)
This answer does not make much sense to me since we are selecting 4 things and not 10 things. Am I right or is the book right?
Thanks