DO NOW 02/13 To raise new questions, new possibilities, to regard old problems from a new angle, requires creative imagination and marks real advance in science. -Albert Einstein What does this quote say about science? About life in general?

DO NOW Draw a histogram for the following scores out of 100 points. 80, 40, 45, 50, 62, 76, 78, 91, 34, 74, 72, 66, 87, 49, 56, 59, 52, 78, 91, 98, 55, 63, 18, 23, 35 Estimate what your average is. What is your range of values? Describe your shape. Rate on a scale of 1  4

NO.

NO. What was wrong with her technique? Why was this so painful to watch?

WHAT IS OUR QUESTION With your partner, build a question that you are interested in asking the MAHS population? Elaborate on your mode of attack: how will you obtain your info? Who will you ask? How many? Write down your essential question.

Today we will… 3.4 Build questions that are free from bias, clear, and focus on what I want to ask my sample 3.6 Use a variety of sampling methods to obtain sample data from a population

SAMPLING AND ASKING

HOW TO ASK First thing first, whenever you conduct a study within a population, you want to communicate clearly with your audience what you are researching, and ASK them if they could answer a few questions. For example: “Hi my name is _______ I am researching how many different ages are in the neighborhood, would you care to answer a few questions, this will only take a few seconds of your time.”

HOW TO ASK If they request not to be bothered, simply thank them and let them go. The trick is BE POLITE. BE COURTEOUS. BE RESPECTFUL When it comes to language barriers, you should be prepared ahead of time and understand what languages might be dominant in your area. Have a script ready so you can clearly address any questions they might have. Always be prepared to answer questions. Some common questions you might receive are: What is this for? What will you do with my information? Do you need my name/address/other identifying information? Who will see this?

HOW TO ASK In our case, you would address these questions by telling your participants that this is for a human population project and your environmental class is interested in finding how many people live in your area. You do not need identifying information—unless you personally would like to achieve this in addition to the project— and their information will be isolated within the confines of our classroom.

HOW TO SAMPLE There are a variety of methods used to carefully sample our population. We will be discussing 2-3 strategies and explaining how we can use these in our project.

STRATIFIED SAMPLING 1.Stratified sampling: This method requires that you divide your population into groups and then select individuals from each group. For example, if I wanted to survey MAHS about their GPA’s I would divide my population by grade level: 9 th, 10 th, 11 th, and 12 th graders and pick 20 students from each grade level to represent my entire population. My strata are the grade levels that I divided my large group into.

SIMPLE RANDOM SAMPLING (SRS) Simple Random Sampling: This method says there are N people in our population and there are n people in our sample, and they all have the SAME CHANCE of being randomly selected. This method is ideal if you have a list of individuals that you can randomly select ahead of time. If we wanted to sample MAHS, we would have the list of students that attend here and randomly select them. We could do this by assigning each student a number, then blindfolded, picking a few numbers from a hat and those will be our sampled students. Or we could stand outside the hallway and just ask everyone, since they all have equal chance of being asked.

SRS

QUICK CHECK Explain/draw/define what stratified sampling is. Give an example Explain/draw/define what simple random sampling is. Give an example.

SYSTEMATIC RANDOM SAMPLING Systematic Random Sampling: with this strategy, you would develop a system in which you would still RANDOMLY pick individuals from your population. For example, if you were outside in the hallways during lunch, you and your partner would pick every third person that walked by as the person you would ask. Or maybe every 20 seconds, etc. You would establish your own parameters, but you must CHOOSE RANDOMLY.

SYSTEMATIC SAMPLING

QUICK CHECK Define/draw/describe what systematic sampling is. Give an example Distinguish between stratified sampling and systematic sampling.

MORAL OF THE STORY The moral of the story is you need to be random. That means that you can’t wait for the friendliest looking person to walk by and only ask them, or only ask people you personally identify with etc. For your study to be taken seriously you must approach individuals without internal biases—preconceived ideas—or else your data might be skewed or not truly representative. For you, you might feel more comfortable approaching people who are around your age. But we know that that is not the true representation of our neighborhood, so your research is not valid.

BIAS QUESTIONS Bias refers to any personal preferences or objections to a specific topic/action/or group. In order for our study to be legitimate, we want to avoid being biased when selecting our individuals. Our questions are simple: How many individuals are in your household? What is their age? You DO NOT ask: How many teenagers live in your household? Do you have any little kids? How many old people live in your household? Biased questions such as these, limit the freedom to the response your participant can make. For us, asking these questions will lead to inaccurate results and won’t give us all the information we might need to get a better graphic for what our population looks like.

PRACTICE FEB 24 (2+4) You will pick a partner for this mini-project You will need to work together and conduct a mini-study: 1.Find a partner YOU KNOW you will work well with. Work>Friends 2.Find out who you are interested in sampling: teachers, students…etc. and how many 3.Develop a QUESTION you are interested in asking your population 4.Develop a SAMPLING METHOD you will use to ask your question 5.Figure out what type of data you’re obtaining: categorical or continuous 6.What type of graph will you use to best represent your data? 1.What’s your average—if you have one? 2.What are patterns/trends you see? 7. What does your data tell you about your population?

DO NOW 02/13 1.What is your survey question for your project in this class? 2.What are the 3 sampling methods? Describe one method and how you will use it. 3.Explain why bias is not beneficial to your study 4.Rate yourself on a scale of 1  4