simulated_freqs: simulated frequencies at different confidence intervals
Arguments
n
desired populations size (set this value same as your actual
population size for an accurate simulation)
nrun
number of simulations to run on each allele frequency.
The higher this number, the closer the simulations will be to the
theoretical values (at the cost of computer power); 10000 is an optimal value.
res
desired resolution of the theoretical allele frequency