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Lesson Menu Five-Minute Check (over Chapter 11) Then/Now New Vocabulary Key Concept: Data Collection Techniques Example 1:Classify Data Collection Techniques Example 2:Identify if the Sample is Valid Key Concept: Random Samples Example 3:Classify a Random Sample

Vocabulary sample population survey observational study experiment biased sample random sample simple random sample stratified random sample systematic random sample

Concept

Example 1 Classify Data Collection Techniques A. RETAIL Each day, a department store chain selects one male and one female shopper randomly from each of their 57 stores and asks them survey questions about their shopping habits. Identify the sample and determine the population from which it was selected. Answer:The sample is the 114 shoppers each day. The population is all the shoppers in the chain’s stores.

Example 1 Classify Data Collection Techniques B. RETAIL Each day, a department store chain selects one male and one female shopper randomly from each of their 57 stores and asks them survey questions about their shopping habits. Classify the type of data collection used by this department store. Answer: This is a survey. The data are from responses given by people in the sample.

Example 1 A.The sample is all college students. The population is college students in his dorm. B.The sample is a college student. The population is all college students. C.The sample is college students in his dorm. The population is all college students. D.The sample is Mark. The population is college students in his dorm. A. Mark, a college journalist, wanted to find out what the average student in the United States does on the weekend. He decides to interview people in his dorm. Identify the sample, and suggest a population from which it was selected.

Example 1 A.survey B.observational study C.experiment D.none of the above B. Mark, a college journalist, wanted to find out what the average student in the United States does on the weekend. He decides to interview people in his dorm. Classify the type of data collection used by Mark.

Example 2 Identify if the Sample is Valid A. STUDENT COUNCIL The student council surveys the students in one classroom to decide the theme for the spring dance. Identify the sample as biased or unbiased. Explain your reasoning. The sample includes only students in one classroom. Answer: The sample is biased.

Example 2 Identify if the Sample is Valid B. SCHOOL The Parent Association surveys the parents of every fifth student on the school roster to decide whether to hold a fundraiser. Identify the sample as biased or unbiased. Explain your reasoning. The parents are picked randomly and all have a chance of being picked. Answer: The sample is unbiased.

Example 2 A.unbiased B.biased C.cannot be determined A.A local news station interviews one person on every street in Los Angeles to give their opinion on their mayor. Identify the sample as biased or unbiased.

Example 2 A.unbiased B.biased C.cannot be determined B.A statistics company calls every twentieth person in Cleveland’s telephone directory to find out his or her favorite sports team in Ohio. Identify the sample as biased or unbiased.

Concept

Example 3 Classify a Random Sample A. COMMUNITY A neighborhood is divided into blocks. Then three residents are selected from each block for a survey on hours of operation for the community pool. Identify the sample, and suggest a population from which it was selected. Answer:Sample: three residents from each block; population: the residents of the neighborhood

Example 3 Classify a Random Sample B. COMMUNITY A neighborhood is divided into blocks. Then three residents are selected from each block for a survey on hours of operation for the community pool. Classify the sample as simple, stratified, or systematic. Explain your reasoning. Answer:Stratified; the neighborhood is divided into categories before there is a random sample.

Example 3 A.The sample is every tenth item. The population is all of the products that are manufactured in the factory. B.The sample is all products that are manufactured in the factory. The population is every tenth item. C.The sample is a car. The population is all cars. D.The sample is unbiased. The population is all cars. A. At an automobile factory, every tenth item is checked for quality controls. Identify the sample and suggest a population from which it was selected.

Example 3 A.simple random sample B.stratified random sample C.systematic random sample D.none of the above B. At an automobile factory, every tenth item is checked for quality controls. Classify the sample as simple, stratified, or systematic.

End of the Lesson