- Thread starter Compliance Carl
- Start date

Why does sample size impact the *rate* of defects in your opinion? I mean surely it would change the raw count of defects but not really the rate in a significant way.

This might help. You can calculate the probability of Group B finding their number assuming that things are perfectly random using the hypergeometric distribution.

In Excel type =HYPGEOMDIST(number group B found,number Group A found,Total in Group B sample,Total in group A sample)

So, Group A found 15 defects in 200. Group B found 3 defects in 10 from the same set. How likely is that?

=HYPGEOMDIST(3,15,10,200) = 0.027 about 1 chance in 40 - fairly unlikely. You can now make a decision about the two groups.

This might help. You can calculate the probability of Group B finding their number assuming that things are perfectly random using the hypergeometric distribution.

In Excel type =HYPGEOMDIST(number group B found,number Group A found,Total in Group B sample,Total in group A sample)

So, Group A found 15 defects in 200. Group B found 3 defects in 10 from the same set. How likely is that?

=HYPGEOMDIST(3,15,10,200) = 0.027 about 1 chance in 40 - fairly unlikely. You can now make a decision about the two groups.