point estimator

a function of the random variable used to make inferences about the value of an unknown population parameter.

point estimate

the value of the point estimator derived from a given sample

unbiased

if the expected value equals the unknown population parameter being estimated

efficient

when an unbiased estimator has a standard error that is lower than that of unbiased estimators

consistent

if an estimator approaches the unknown population parameter being estimated as the sample size grows larger

confidence interval

provides a range of values that, with a certain level of confidence, contains the population parameter of interest

degrees of freedom

determine the extent of broadness of the tails of distribution; the fewer the degrees of freedom, the broader the tails.