AI engineering glossary · Statistics inference
What is Cramér-Rao bound?
Cramér-Rao bound: A lower limit on the variance of any unbiased estimator of a parameter, equal to the reciprocal of the Fisher information. It shows the best precision that is theoretically possible from the data.
Cramér-Rao bound: an example
For a coin with p = 0.5 and n = 100 flips, no unbiased estimator of p can have variance below 0.25 / 100 = 0.0025.
Related terms
More Statistics inference terms
- Credible interval
- Critical value
- Degrees of freedom
- Difference-in-differences
- Effect size
- Efficiency
- Estimator
- F-test
Where you learn it
Cramér-Rao bound is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.