Warm-up A.P. Statistics and Statistics 4.1 How to samples When information is gathered from the entire population it is called a census. More often, information is gathered from only a sample(part of the population). 1) List reasons information is often taken from samples instead of the entire population. 2) There are some better ways to gather a sample. What are inferior ways to select a sample that might bias the information that you are gathering?

4.1 How to take sample notes Census Versus Sample D1. In which of these situations do you think a census is used to collect data, and in which do you think sampling is used? Explain your reasoning. a. An automobile manufacturer inspects its new models. b. A cookie producer checks the number of chocolate chips per cookie. c. The U.S. president is determined by an election. d. Weekly movie attendance figures are released each Sunday. e. A Los Angeles study does in-depth interviews with teachers in order to find connections between nutrition and health

Student of the day! Block 4

Student of the day! Block 5

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Bias: A Potential Problem with Survey Samples offer many advantages, but some samples are more trust- worthy than others. * bias in the way you select your sample * a nonrepresentatitive sample is when it does not represent a miniature version of the sample Classic Example: Literary Digest predicting election results * bias in the way you get a response from the units in your sample – this is also known as response bias Asking questions face-to-face; non-anonymous surveys A sampling method is biased if it produces samples such that the estimate from the sample is larger or smaller, on average, than the population parameter being estimated.

Methods of Sampling

Volunteer sample: Convenience sample: Judgment sample:

Diagram from pg 240

Response Bias Non-response bias Questionnaire bias Incorrect bias Pg 226

More Discussion Questions pg 225 D4 Identify the type of sampling method used in each of the surveys? Would you expect the estimate of the parameter to be too high or too low. Explain your reasoning. Type of SamplingToo high/too low a. b. c.

H.W. Assignment A.P.Statistics: H.W. 4.1 E #1,2,6 and 7; 4.2 E #15 and 16 and #22 Statistics: H.W. 4.1 E #2-6 all problems