Statistics?

Does anyone know what a confidence interval in statistics is and provide an example?





Maximum error of estimate? Example also?

Statistics?
A confidence interval in statistics provides a range of plausible values for a parameter of interest. For example, you may have heard something like the following about a survey or political poll:





48% of people support candidate x with a margin of error of plus or minus 2.





Well, that "plus or minus 2" puts a confidence interval around the point estimate of 48%. Instead of just giving 48 as the estimate, you could give the confidence interval:





(46, 50)





As for the maximum error of estimate...
Reply:A CI is a interval centered about a sample statistic that is used to provide an idea about the true value of the population parameter. The CI has a size and we say that we are 95% confident the true value of the parameter is with in the limits of the interval. An example for a large sample CI for the mean with size 95% is:





xBar ± 1.96 * sx/Sqrt(n)





where xbar is the sample mean


1.96 is the standard z score for a 95% interval


sx is the sample standard deviation


n is the sample size.





the maximum error of an estimate? Well look up propagation of error. The estimator is a function of something and if you use the propagation of error formula you will find the error in the estimator. the equation requires some partial derivatives and is to difficult to type out cleanly here so I will direct you too look at this page:





http://mathworld.wolfram.com/ErrorPropag...

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