PS102Lecture9

# PS102Lecture9 - Sampling and Statistical Inference...

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Sampling and Statistical Sampling and Statistical Inference Inference Political Science 102 Introduction to Political Inquiry Lecture 9

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Populations and Samples Populations and Samples We cannot observe population parameters Use samples to draw inferences about populations What is best estimate of population value? Probability samples allow use of statistics to estimate precision How far off is sample statistic likely to be?
Statistical Vocabulary Statistical Vocabulary Expected Value Average value of a random variable Standard Error / Deviation Average variation of random variable from its expected value Sampling Distribution Probability distribution of a random variable with sample size = n

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Statistical Estimators Unbiased Estimator Sample statistic with expected value equal to the population parameter In any single sample the estimator may not equal the value of the population parameter Statistic equals population parameter on average over many samples
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## This note was uploaded on 10/21/2011 for the course POL SCI 102 taught by Professor Gelpi during the Spring '11 term at Duke.

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PS102Lecture9 - Sampling and Statistical Inference...

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