The B (225, 1/5) distribution can be approximated by what normal distribution?

The general formula for approximating B (n, p) via a normal distribution is to let the mean be np and the standard deviation be sqrt[n*p * (1-p) ]. For this case, n = 225 and p = 1/5.

The mean np = (225) (1/5) = 45, and

The standard deviation sqrt[np (1-p) ] = sqrt[ (225) (1/5) (1 - 1/5) ] = 6

This can be approximated with the normal distributino of mean 45 and SD 6.