Statistics Simplified: Sampling Methods Explained
Join Markayla in an interactive AP Statistics challenge. Learn about sampling methods like SRS, Probability, Strata, and Clusters. Understand how to reduce bias and design an unbiased study.
Statistics Simplified: Sampling Methods Explained
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Presentation Transcript
Markayla Needs Your Help! An AP Statistics Challenge
During this Presentation… • College-Style! • You will take notes on WHAT YOU HEAR as well as WHAT YOU SEE • Do NOT GIVE UP & LISTEN INTENSELY! • Record on your graphic organizer!
What do we know so far? • Convenience Sample - Markayla takes a sample of individuals who are easily accessible, but do not represent the population Voluntary Response Sample - Markayla takes a sample of volunteers.
Simple Random Sample (SRS) If Markayla’s population is the entire student body at Fenger, then how would she collect a Simple Random Sample (SRS) for this study? • Assign every student in the school a number • Use her graphing calculator or Random Digit Table to select a sample of n students • These students will be in the study
Probability Sample • A sample chosen by chance Types of Probability Samples are: • Simple Random Sample • Stratified Simple Random Sample • Cluster Sample
Thinking about an SRS • By taking an SRS, then how would Markaylareduce bias in her study? - The SRS represents the population, because every individual in the school has a chance of being selected. • How is an SRS still biased? - Nonresponse - Undercoverage
Stratified Simple Random Sample • Divide students into “strata” or groups, such as grade level or gender • Choose an SRS in EACH strata • Go back to first example and let’s see what it looks like
Cluster Sample • Divide the population into groups, or clusters. Then, all individuals in the chosen clusters are selected to be in the sample. • What Markayla could do: - Divide Fenger student body into “social groups”, such as “jocks”, “nerds”, “skaters” - Then, select all the students in certain groups to take her survey
