ISDS 2000 Chapter : Stat Ch 8
15 Mar 2019
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Point estimate: consists of a single sample statistic used to estimate the true value of the population parameter (either or ) Interval estimate: an estimate constructed that is believed to contain the true population mean. Levels of conficence: 90% or . 1 = 1. 645, 95% or . 05 = 1. 96, 99% or . 01 = 2. 575. As the confidence increases, z increases, margin of error increases, and the confidence interval gets wider. When is unknown, then to standardize the sample means, we must use (xbar - xbar)/(s/ n) For categorical variables, remember that the parameter of interest is the population proportion of successes, . General form of the confidence interval for proportions: ci(1- ) = p z /2 ( (p/(1-p))/n)
