Statistics
Complement of an event
The probability that the event does not happen. Useful when counting the ways something fails is easier than counting the ways it succeeds.
The Formula
P(not A) = 1 - P(A)
The probability that the event does not happen. Useful when counting the ways something fails is easier than counting the ways it succeeds.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| P | Probability of the event | dimensionless | Between zero and one. |
| Pc | Complement | dimensionless | One minus the probability of the event. |
What Each Symbol Means
Pdimensionless
Probability of the event
Between zero and one.
Pcdimensionless
Complement
One minus the probability of the event.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate probability page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate Probability, filed under Math. Every number the guide produces comes from substituting into this one line.