STAT 100 Lecture Notes - Lecture 3: Simple Random Sample, Bias Of An Estimator, Convenience Sampling

• School: Simon Fraser University
• Department: Statistics
• Course: STAT 100
• Professor: Gamage Perera

Document Summary

Gallup poll, 2015: randomly selected 1504 american adults. Found that 53% of sampled adults disapproved of the affordable care act (aca), the. Parameter: a number that describes a population in some way. (population proportion) Statistic: a number that describes a sample in some way. Key difference: in practice, we usually never know the actual value of a parameter. (parameter is unknown) (because we don"t have data on the whole population) In contrast, we can calculate the value of a statistic based on the sample data, which we do have. (statistic is known) So . we often use the value of the statistic to estimate the unknown value of the parameter. This is an unknown parameter we denote a population proportion by p. To estimate p, here, we can calculate the proportion in the sample opposing the aca. This is a statistic which estimates the parameter we denote a sample proportion by p (pronounced p-hat ).