Probability: A lot of 300 with 2% defective. Find the proba

[Paul Suszko]

A lot of 300 with 2% defective. Find the probability that 2 or more defective parts will be drawn from a sample of 40.

 

[tkhunny]

Pr(2 or more) = 1 - (Pr(0) + Pr(1))

 

[Paul Suszko]

Why does the CQT primer answer arrive at .191 probability of 2 or more defective ?

 

[pka]

Why does the CQT primer answer arrive at .191 probability of 2 or more defective ?

Your study guide is assuming that because of the numbers involved the distribution can be viewed as ‘binomial’.
I have done the problem both ways.
With binomial one gets .19046.
Using combinations of 6 and 294 we get .183808.
It is not a huge difference.

 

[Paul Suszko]

Thanks again.