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Unformatted text preview: What is Statistics? Statistics is the science of collecting, summarizing, analyzing and interpreting data. Statistics involves methods for Designing and carrying out research studies. Describing collected data. Making decisions, predictions, or inferences about phenomina represented by data. Some Definitions A Population is the entire collection of objects or outcomes about which in- formation is sought. A Sample is a subset of a population, containing the objects or outcomes that are actually observed. A Simple Random Sample (SRS) of size n is a sample chosen by a method in which each collection of n population items is equally likely to comprise the sample. Ex 1. A physical education professor wants to study the physical fitness level of students at her university. There are 20 , 000 students in the university and she draws a sample of size 100 to take a physical fitness test. The physical education professor obtains a list of all 20 , 000 students, numbered from 1 to 20 , 000. She uses a computer number generator to generate 100 random integers between 1 and 20 , 000. She invites the 100 students corresponding to those numbers to participate in the study. The population of interest: 20 , 000 students in the university. The sample: the 100 students chosen to take the physical fitness test. The simple random sample: Yes. Ex 2. A quality inspector samples 40 bolts from a large shipment and measures the length of each to see whether they meet a length specification....
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- Spring '08