# Stats: Estimation

## Definitions

- Confidence Interval
- An interval estimate with a specific level of confidence
- Confidence Level
- The percent of the time the true mean will lie in the interval estimate given.
- Consistent Estimator
- An estimator which gets closer to the value of the parameter as the sample size
increases.
- Degrees of Freedom
- The number of data values which are allowed to vary once a statistic has been
determined.
- Estimator
- A sample statistic which is used to estimate a population parameter. It must be
unbiased, consistent, and relatively efficient.
- Interval Estimate
- A range of values used to estimate a parameter.
- Maximum Error of the Estimate
- The maximum difference between the point estimate and the actual parameter. The
Maximum Error of the Estimate is 0.5 the width of the confidence interval for means
and proportions.
- Point Estimate
- A single value used to estimate a parameter.
- Relatively Efficient Estimator
- The estimator for a parameter with the smallest variance.
- T distribution
- A distribution used when the population variance is unknown.
- Unbiased Estimator
- An estimator whose expected value is the mean of the parameter being estimated.

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