estimator
an estimator is a rule for calculating an estimate of a given quantity based on observed data.
for a given sample
, the broken link: blk:1700646052 of the estimator 
defined as 
, where 
is the parameter being estimated. the error, 
, depends not only on the estimator (the estimation formula or procedure), but also on the sample.
the mean squared error of is defined as the expected value (probability-weighted average, over all samples) of the squared errors; that is, 
.
it is used to indicate how far, on average, the collection of estimates are from the single parameter being estimated.
https://en.wikipedia.org/wiki/Estimator
for a given sample
, the broken link: blk:1700646052 of the estimator defined as , where is the parameter being estimated. the error, , depends not only on the estimator (the estimation formula or procedure), but also on the sample.the mean squared error of
is defined as the expected value (probability-weighted average, over all samples) of the squared errors; that is, .it is used to indicate how far, on average, the collection of estimates are from the single parameter being estimated.
https://en.wikipedia.org/wiki/Estimator