 # Population correction factor

We use a finite population correction factor when n (the sample) represents more than 5% of N (the population). When we determine this pcf as per the formula, where exactly do we apply it? Thanks

Dude, i have no idea what any of that means and it has me quite worried. Please tell me you are a level II who got lost and ended up here.

It’s from level I quant and it has to do with confidence intervals, samples, populations, etc. It’s mentioned in a footnote and in some of the questions, but I don’t see it applied, so I’m not sure whether it will be tested or not. Basically when we’re constructing confidence intervals, we need to know the size of the sample to determine whether we should use z-tests or t-tests (n>= 30 we can use z-test). But the book also mentions that if the sample represents 5% or more of the population, then we need to use a population correction factor, which is: = [(N-n)/(N-1)]^(1/2) * (pop. s.d./n^(1/2)) I haven’t seen it used anywhere so not sure where the number generated from that formula would be applied…

I guarantee you will not need to know that on the exam. It’s pretty obscure statistics (I don’t know it off the top of my head and I’ve taught statistics class 80 times or something).