Warm Up – 5/13 - Tuesday Mr. Gill is planning the prom. In order to find out what the students want to eat at the prom he polls his math classes. That semester he is teaching AP Calculus, Honors Common Core 1, and Honors Common Core 2. Write in complete sentences any problems you see with Mr. Gill’s plan.

Surveys A survey is a method of collecting information. The group being studied is called the population. The most effective way to gain information would be to poll the entire population. To save time and money we poll a sample.

Sample vs. Population

Biased and Unbiased Samples A survey’s bias skews the results of our survey. When we make our survey, we want our survey to be as unbiased as possible in order to get the most accurate information about the population.

Types of Random Samples Systematic Random Samples: When a survey uses a specific pattern to select its participants. This is a valid and unbiased method. Convenience Samples: A sample where responses do not represent the entire population. This is done by only surveying a convenient sample of people who are nearby. This is biased and is not a valid random sample.

Samples Continued Voluntary Response Samples: Voluntary Response Samples are one in which the responses are entirely voluntary. This is a biased and is not a valid random sample. Example: An internet survey asks if North Carolina residents support Sunday Hunting.

This survey was actually done twice This survey was actually done twice. Once by phone and once by the internet.

Valid Conclusion?

Valid Conclusions

Biased vs. Unbiased Samples CW