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Sampling Error

Sampling Error. Measures the likelihood of random error due to using a small sample rather than the complete populaiton Assumes a random sample. Sampling Error: Short formula.

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Sampling Error

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  1. Sampling Error • Measures the likelihood of random error due to using a small sample rather than the complete populaiton • Assumes a random sample

  2. Sampling Error: Short formula

  3. Results from the entire sample have a statistical margin for error of ± 3.4 percentage points at the 95 percent confidence level. This means that if we were to conduct the survey 100 times, in 95 of those instances the results would vary by no more than plus or minus 3.4 points from the results obtained here. The margin for error will be larger for demographic, geographic, and response subgroups.

  4. “Quinn leads Dems, Republican front-runner unclear for 2010 governor's race” • Illinois Gov. Pat Quinn leads his rival for the Democratic gubernatorial nomination, Comptroller Dan Hynes, by a two-to-one margin • among likely primary voters, • link

  5. Random Sample? • Assumption: Non-respondents the same as respondents • Problems: • Refusals • Cell phones • Unlisted numbers • Adjustments: esp. likely voters • Internet polling?DH survey

  6. Table 1.2 Press Reporting of Polling Reliability

  7. % Change, Index Crime Rates, Florida Counties 2007-8

  8. % Change, Index Crime Rates, Florida Counties 1998-08

  9. Robbery Rates, Ten Largest Cities, 1985-2007*BJS: Data Online

  10. Revised:Officers Assaulted in Florida, 1991-2008

  11. Percent of GDP spent on health care, Life Expectancy in OECD countries for 2006

  12. Foreign-born: % of population, 2005

  13. “Husband’s job to earn money; wife’s job family”% Strongly Agree

  14. Violent Crime Rates, Chicago and New York City, 1985-2007 (offenses per 100,000 population)

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