Warm-upA.P. Statistics and Statistics 4.1 How to samples

When information is gathered from the entire population itis called a census.

More often, information is gathered from only a sample(part of thepopulation).

1) List reasons information is often taken from samplesinstead of the entire population.

2) There are some better ways to gather a sample. What areinferior ways to select a sample that might bias theinformation that you are gathering?

4.1 How to take sample notes

Census Versus Sample D1. In which of these situations doyou think a census is used to collect data, and in which doyou 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

Student of the day!Block 6

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 suchthat the estimate from the sample is larger or smaller, onaverage, 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 biasPg 226

More Discussion Questions pg 225D4 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 Sampling Too high/too lowa.

b.

c.

H.W. AssignmentA.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