A binomial distribution is an experiment where there are
two outcomes; Success and failure. For instance, you are given n = 128 and p = 0.27.
The formula for the variance of a binomial distribution is n*p(1 – p) or
n*p*q*. They are equivalent because q = 1- p. We will use the first equation.
Variance = n*p*(1 – p)
Variance = 128*0.27*(1 – 0.27)
Variance = 25.23
To get the standard deviation, find the square root of
the variance.
Standard deviation = sqrt (Variance)
Standard deviation = sqrt (25.23)
Standard deviation
= 5.02
