Do Now For your senior project, you are studying first generation college graduates. You are interested in knowing what percent of KIPP students will be the first person in their family to attend college. In order to conduct your study, you will ask 50 KDCA students if their parents or grandparents attended college. Identify the individuals and variables of interest. Identify the population and the sample. Is this an experiment, observational study, or sample survey?

Sampling Methods Unit 1: Univariate Data

Objectives Identify method of reliable sampling and others ways to reduce bias and variability Demonstrate mastery on Illuminate Quiz 

Sampling Sample should be representative of the population in order to make inferences. This means the sample must be as randomly chosen as possible. A sample is biased if the sample is not representative of the population. Framework for why sampling methods are essential and how they relate to randomization.

Sampling Methods for a Representative Sample Process Example Simple Random Sample (SRS) Chosen in a way that every individual in the population has an equal chance to be selected for the sample Ex: Put the names of students in a box, mix the names, and draw 50. Students mix M+Ms together and randomly select 5

Sampling Methods for a Representative Sample Students organize M+Ms by color and randomly select 1 from each group.

Sampling Methods for a Representative Sample Divide MMs into 3 random groups and select one group as sample

Sampling Methods for a Representative Sample Line up MMs and select every 3rd as sample

Sampling Methods for a Representative Sample Process Example Simple Random Sample (SRS) Chosen in such a way that every individual in the population has an equal chance to be selected for the sample Ex: Using technology to create a random table of digits, pick 50 KDCA students by ID number. Stratified Random Sample Divide the population into strata of individuals that are alike and take an SRS from each strata. Ex: Divide students by grade and take an SRS from each grade. Cluster Sample Divide the population into clusters that are representative of the overall population and sample every individual in a few clusters Ex: Choosing 5 reading interventions from KDCA and sampling every student. Systematic Sample Sample every nth individual in a population Ex: Sample every 5th person who walks in the door to school.

Methods that create Biased Samples

Sample Quiz Question

Did we accomplish our objective? Connection to college or career

Illuminate Quiz 

Before reading discussion (activate prior knowledge)

Homework and Independent Practice Read and respond to Gallup Poll Questions Khan Academy: Types of Statistical Studies