Parameters - descriptive measure of an entire population however their values are usually unknown
it's not feasible to measure an entire population and because of this a sample from the population is taken to obtain parameter estimates
Sample Statics - estimate of the population parameters along with the amount of error associated with these estimates
Estimation - Process of estimating or approximately calculating the value of a parameter from information drawn from the samples
the object of estimation is to determine the approximate value of population parameter based on the basis of sample statistics
one aspect of inferential statistics because we get approximate values from the population parameter from the information drawn from a sample
Estimator - the estimator of the population parameter is the sample statistics
-attempts to approximate the unknown parameter using measurements
Estimate - the computed sample statistics
Point Estimates - single most likely value of a sample statistic that is used to estimate a population parameter
Properties of Desirable Estimator:
Unbiased - happens when the mean or expectation of the statistic is equal to the parameter
Consistent - the difference between the estimator and the parameter becomes smaller as the sample size grows bigger
Relatively Efficient - if there are two unbiased estimators of a parameter, the one whose variance is smaller should be used
Interval Estimates - or confidence Intervals are a range of values to estimate a parameter
a degree confidence, ususally a percent, can be assigned before an interval estimate is used
confidence lies with some region with some prescribed probability
confidence level is associated with a confidence interval which states how much confidence we have that the interval contains the true population parameter
the more frequent values for a confident interval are 99% , 95% . and 90% with corresponding margin of errors 1%, 5%, 10%
Margin of Level - refers to the maximum acceptable difference ( determine by a) between the observed sample statistic and the true population parameter