Biology 2244A/B Study Guide - Final Guide: Georgia State Route 2, Unimodality, Bias Of An Estimator
1 Jan 2017
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How good is the statistic p hat an estimate of the parameter p: ask, (cid:498)what would happen if we took many samples? (cid:499) Behavior of sample proportion p hat is similar to the behavior of sample means x bar: when the sample size is large, the sampling distribution is approximately normal. The mean of the sampling distribution of p hat is the true value of the population proportion, p. The standard deviation of phat is sqrt(pq/n: gets smaller as the sample size gets larger at a rate of root n. The normal approximation to the sampling distribution of p hat is least accurate when p is close to 0 or 1. Confidence levels and p-values are probabilities calculated from the sampling distribution of p hat. 19. 2 large-sample confidence intervals for a proportion. To estimate a population proportion, use the sample proportion p hat.
