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Published byShanon Underwood Modified over 9 years ago
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1. When I give you the signal, you will have 10 seconds to look at a slide and make a guess as to the average number of m&m’s per pile. Do not use pencil or paper… just guess.
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On Word Document
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Population-entire group of individuals we want information about. Sample-part of the population to represent the population Population Sample
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Observational To gain information w/out influence Experiment Imposes some treatment on individuals to observe response. Use for cause and effect
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Sampling Used to study part of a population to gain information of the whole population Census Attempts to contact every individual in the population.
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Voluntary response People choose to participate Extremely Biased “bad design” Convenience Sample Based on easy access with out looking at representation of the whole population ▪ Example: You want to know if Kimball students like Math so you ask your math class. “bad design”
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Exercise 5.1-5.8
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Simple Random Sample (SRS) Random, everyone has a chance of being picked This is a good Sampling method Stratified Random Sampling Used when you want groups to be equally represented.
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Random, everyone has a chance of being picked Step 1: Label: Assign an numerical value to all the individuals Step 2: Random Assignment ▪ Use the random number table (Table B) ▪ Random number generator (using the calculator) ▪ Math PRB #5:RandInt enter (1,33) ▪ Seed 5 rand Seed #, store, math, PRB, option 1:rand
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Stratified Random Sampling is NOT SRS Step 1: Separate the population into similar groups called strata ▪ For equal representation Step 2: SRS each strata, these SRSs form your sample Choose strata based on facts known before the sample is taken Ex: A population of election districts might be divided into urban, suburban, and rural strata. Every group is represented.
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Randomly choose stage 1 strata Random States in the country Randomly choose stage 2 strata Random cities in the states And so on until you get your sample size.
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Every 5 th person to walk by is interviewed
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Exercise 5.9-5.11
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Undercoverage A group of the population is left out If you use a phone directory to get a sample. You miss out on… Nonresponse No answer, do not mail back etc. Left out of the representation Response Bias Participants are not telling the truth Wording of questions
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We want to make inferences about the population as a whole population. We cant afford to talk to everyone. Note: Two samples following the same design will give you different results. Each one is an estimate of the population.
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Large random samples give more accurate results than smaller samples.
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Read the summary on Pg.285 Exercise 5.19-5.29odd, 26 Plan your Data Collection Sample You need to write your plan on a binder paper ▪ Goal: Describe Population and purpose of survey. ▪ Sample: State Sampling Design, size and plans for implementation. ▪ Foreseen Bias: What are they, Give details on how they apply (ex: undercoverage-who was left out), how do they impact your results. Turn in raw data Display data visually and Describe Summarize your experience collecting the data ▪ Cautions experienced- restate the predicted and additional ones. ▪ Any surprises Due Thursday
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Read the summary on Pg.285 Exercise 5.19-5.29odd, 26 Start your chapter 5 summary You may use diagrams, visuals, bullet points You may not just copy down a list of definitions
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