13.2 Surveys and Samples SWBAT identify populations and samples for surveys SWBAT distinguish biased from unbiased samples SWBAT identify and distinguish among sampling methods SWBAT display and use Venn diagrams to analyze sample data

Vocabulary  Survey: a question or set of questions designed to collect data about a specific group of people  Population: the people used in a survey  Random Sample: a sample chosen without preference

Vocabulary  Bias: anything that favors a particular outcome  Biased Sample: not a representation of the population under study  Voluntary Response: people chose whether or not to participate in the poll

Vocabulary  Convenience: people are polled based on the fact that they are there  Stratified Sampling: a population is broken into subgroups

Identify the sampling method used. Write random sample, voluntary response, convenience, or stratified sampling  Viewers are invited to call in to a TV show to rank contestants  One name is chosen from each page of the phone book  Select every 10 th member of a fitness club to complete a survey and then collect the survey  Select an equal number of random members from the offered exercise classes to complete a survey and collect it

Identify the population and sample. Give a reason the sample could be biased  A dentist asks his patients how often they floss each day  A teacher asks students about their favorite hobbies

Create a Venn diagram to answer the questions:  Students involved in extracurricular activities at Fischer High School were surveyed and the following information was collected: 76 students are members of the band, 76 are members of clubs, 72 are active in sports, 32 are active in the band only, 15 are in the band and clubs, 24 are active in sports only, and 11 are active in sports, the band, ad clubs. How many students are involved in only two extracurricular activities?

Band 32 Clubs 31 Sports

Create a Venn diagram to the right of each question to answer the following:  Students in the twelfth grade at Bernardsville High school were surveyed about their enrollment in art, dance, and dram classes. The following information was collected: 70 students had taken art classes, 50 had taken dance classes, 80 had taken drama classes, 20 had only taken art, 17 had taken both art and dance, 15 had only taken dance, and 10 had taken both dance and drama. How many students had only taken drama classes?

Art 20 Drama 17 Dance