1-3: Sampling Methods Homework 3: p.20 2-10 Learning Objectives: Understand the benefits and burdens of various sampling methods Entry Task: An experiment consists of spinning a spinner 8 times. The spinner lands on red 4 times, yellow 3 times, and green once. Find the experimental probability of each event. 1. The spinner lands on red. 2. The spinner does not land on green. 3. The spinner lands on yellow.

Concept: Sampling Methods A systematic sample is obtained using an ordered list of the population, then selecting members systematically from the list.

Concept: Sampling Methods A stratified sample divides the population into subgroups so that each population member is in only one subgroup.

Concept: Sampling Methods A convenience sample is chosen so that it is the easiest for the researcher to get results

Concept: Sampling Methods In a random sample, each member of the population has an equally likely chance of being selected.

Example 1: Classifying a Sample The campaign staff for a state politician wants to know how voters in the state feel about a number of issues. Classify each sample, Helpers call every 50th person on a list of registered voters in the state A Systematic Helpers select 100 random voters from each county B Stratified because the county is chosen Helpers ask every person who comes to the next campaign rally to fill out a survey C Convenience

Student Led Example 1: Classifying a Sample A new theater gives out free tickets to a premier movie Employees go to a high school and hand out tickets to each passing student A Convenience Employees hand out tickets to customers at Home Depot, Lowe’s and Eagle Hardware B Stratified because of the stores Employees walk down Main St. and give a ticket to every 10th person they see C Systematic

Example 2: Evaluating Sampling Methods A community organization has 56 teenage members, 103 adults and 31 senior citizens. The city council wants to survey the members. Classify each sample method. Which is most accurate? Which is least accurate? Explain. Most Accurate Least Accurate Most accurate as the selection is EQUALLY LIKELY. Least accurate as the selection EXCLUDES anyone not attending the event Random Systematic Stratified

Example 2: Evaluating Sampling Methods A small town newspaper wants to report on public opinion about the new City Hall building. Classify each sampling method. Which is most accurate? Whish is least accurate? Explain Least Accurate Most Accurate Most accurate as the selection is EQUALLY LIKELY. Least accurate as the selection EXCLUDES anyone not attending the event Convenience Convenience Stratified

Activity: Using a Calculator for a Random Sample Please follow the instructions on the provided handout. Use side 1 for your Exit Task.

End of Lesson Consider “rand”, “randInt”, “randNorm” and “randBin”. Classify each of the options as Random, Stratified, Systematic and/or Convenience. “rand” = Random “randInt” = stratified “randNorm” = systematic “randBin” = systematic