lec24 - Statistical inference Question: What is Statistics?...

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Statistical inference Question: What is Statistics? Statistics: is the science and art of studying data. It involves collecting, classifying, summarizing, organizing, analyzing, and interpreting numerical information. More: In general, there are two different processes in statistics: (1) describing sets of data (2) drawing conclusions about the sets of data based on sampling The application of statistics can be divided into two broad areas: descriptive statistics and inferential statistics . Main areas in statistical inference are: estimation of parameters, evaluation of plausibility of values (hypothesis testing), and prediction of future values 1
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An example The share of the credit card market by issuers: this is a descriptive summary of some numerical information 2
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Fundamental elements of statistics (a) Population and sample: Population : all possible measurements or outcomes that are of interest to us in a particular study Sample : a portion of the population that is representative of the population from which it was selected What is the difference? Thinking about an example where we want to know the average height of all people in the world, how can we do that? Can we do that? A population basically has all units of interest; while all of them cannot be observed, a selected subset can be observed and forms the sample . Sample is used to make statement(s) about the whole population. 3
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Fundamental elements of statistics (b) Statistical inference: is the process of drawing conclusions from data that are subject to random variation, for instance, observational errors or sampling variation. Example: A large paint retailer has had numerous complaints from customers about underfilled paint cans. As a result, the retailer has begun inspecting incoming shipments of paint from the supplier. A recent shipment contained
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This note was uploaded on 02/01/2012 for the course STAT 330B taught by Professor Zhou during the Spring '11 term at Iowa State.

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lec24 - Statistical inference Question: What is Statistics?...

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