How this calculation works
Variance is largest at p=0.5. At p=0 or p=1 the result is certain and variance is zero.
THE FORMULA
E[X]=p and Var(X)=p(1−p)A worked example
For p = 0.3 the mean is 0.3 and variance is 0.21.
Good to know
The outcome is binary with the numeric coding 0 and 1.
Reference: OpenStax Introductory Statistics (opens in a new tab) ↗
Read the result
Summarize a single indicator that equals 1 for success and 0 otherwise.
The primary result is labeled “Mean”. Keep the input definitions in view when comparing this result with another method.
Try a related calculation
The outcome is binary with the numeric coding 0 and 1.
For a related exercise, try the statistics calculator.
A few questions, answered
How can I check the default inputs by hand?
For p = 0.3 the mean is 0.3 and variance is 0.21.
Which rule does this calculator apply?
E[X]=p and Var(X)=p(1−p)