Statistics and Research Methods: Sampling and Experiments, Study notes of Data Analysis & Statistical Methods

Download Statistics and Research Methods: Sampling and Experiments and more Study notes Data Analysis & Statistical Methods in PDF only on Docsity! Chapter 12 Sample surveys X1 X2 . . . Xn Population: the entire group of individuals or instances Parameter: numerical characteristic of a population  -population mean deviationpopulation mean deviation  -population mean deviationpopulation standard deviation  -population mean deviation correlation p -population mean deviation proportion Distribution -population mean deviationmodel (density) Sample: a subset of a population Statistic: a number computed from data x -population mean deviation sample mean s -population mean deviation sample standard deviation r – sample correlation p̂ - sample proportion Distribution – histogram, dotplot Vocabulary: Sampling Frame -population mean deviation a list of individuals from which a sample is selected Sampling Variability -population mean deviation each random sample is different Sampling Design -population mean deviation a method of taking a sample Sample Size – the number of elements in a sample If a goal is to estimate population parameters or distribution, a sample should represent the whole population and hence 1. the sample individuals should be selected at random, so that 2. each set of the same size has the same chance of being selected A sample drawn in this way is called a simple random sample (SRS) Sampling Designs  SRS - each set of size n has the same chance to be selected  Stratified Random Sample - a sampling design in which the population is divided into groups (strata) and random samples are then drawn from each stratum  Cluster Sample - a sampling design in which first groups or cluster are chosen, and then samples are drawn within them.  Multistage Sample - design that combines the above methods  Systematic Sample - there is pattern in selecting a sample, but the starting point is random