Sampling Distributions in Econ 472: Understanding Estimators
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Explore how to estimate population mean using 10 draws from a Uniform distribution, analyzing unbiased estimators and their sampling distributions in Econ 472. Discover the efficiency of different estimation rules. Visualize the histograms of estimators to comprehend their variance and bias.
Sampling Distributions in Econ 472: Understanding Estimators
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Sampling Distributions Econ 472
The Design • Consider taking 10 draws from a Uniform distribution on (0,1). [That is, randomly drawing a number between 0 and 1]. One can show that if a random variable X has such a distribution, then E(X) =.5 and Var(X) =1/12. Econ 472
The Design, Continued • Let x1, x2, , x10 denote this collection of 10 draws. • Consider two different rules for using this data to estimate E(X) = x: • and Econ 472
The Design, Continued • Both of these estimators are unbiased, since • (The fact that our first estimator is unbiased was proven in class). Econ 472
The Design, Continued • To obtain the sampling distribution of both estimators, we first obtain 5,000 different sets of 10 draws from this uniform distribution. • For each set of 10 draws, we calculate both estimates. • We summarize the 5,000 estimates from each estimator in the following histograms: Econ 472
Results for Sample Mean • As you can see, the sample mean is an unbiased estimator of the population mean x, as the sampling distribution is centered around E(X) = .5. Econ 472
Results for Second Estimator • Again, this is an unbiased estimator of x. • However, it is slightly less efficient than the sample mean, (i.e., it has a larger variance). • This becomes a little more clear when plotting the sampling distributions on the same graph: Econ 472