What does the 'Influence Function' IF(x;T,F)IF(x; T, F)IF(x;T,F) quantify in robust statistics?
The effect of an infinitesimal contamination at point xxx on the estimator TTT.
The correlation between the estimator and the data.
The rate at which the estimator converges to the true value.
The probability that the estimator TTT rejects the null hypothesis.