Estimation and Sample Size Determination for Finite Populations. Basic Business Statistics: Global Edition.

In Section 7.6, you used the finite population correction (fpc) factor to reduce the standard
error by a value equal to When developing confidence interval estimates
for population parameters, you use the finite population correction factor when samples are
selected without replacement from a finite population. If more than 5% of the population is
sampled (i.e., ), the finite population correction factor significantly reduces the
width of the confidence interval. If less than 5% of the population is sampled, the finite population
correction factor has little or no practical effect on the confidence interval width.
Equation (8.12) defines the confidence interval estimate for the mean.