STAT 11300 Lecture Notes - Lecture 1: Statistic, Statistical Parameter, Sampling Distribution
21 Oct 2016
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Variable: something being measured; characteristic of an individual. Census: attempts to get info from every member of population: time consuming, expensive, and hard to do. Sample: part of the population that we can examine to gather info about whole population: cheaper, quicker, and easier than census. Statistic: number that is true for sample. Bias: consistent deviation of sample statistic from population parameter in same direction: choosing random sample will reduce bias. Variability: how spread out sampling distribution is for the statistic; determined by sampling design and size: larger samples have smaller variability. We want both small bias and variability. Convenience sample: selects individuals easiest to reach: not random, not the best, ex: shopping mall survey. Random sample: eliminates bias by allowing impersonal chance to do the choosing: gives all individuals an equal chance to be chosen, types of random sampling:
