STAT 100 Lecture Notes - Lecture 13: Global Warming, Sample Size Determination, Standard Error
Document Summary
What does the population think: survey of american adults and we want to know whether or not global warming is exaggerated. Used random sampling it is representative. Sample error- not getting the whole picture each sample won"t be exact same. Margin of error- 3% with a 95% confidence: not getting whole picture, how wrong can the estimate be. +- 3% margin of error creates a range. Range= 38%-44: can catch a really good chance that this will be in range next time we test it, 95% confidence. Degree in which we believe this can be true. If we take a new sample of 1,012 there is a good chance that the results stay between 38-44% If we do it 100 times 95 of those would be within margin of error (3%) Quantitative variable: people have to respond with a number. Range 38-44: based on 95% error. 2x square root of . 41(1-. 41) = . 03 = 3%
