Understandable Statistics

1. Understandable Statistics Chapter 1

2. 1.1 What is Statistics? • What does statistics mean to you? • How is statistics used? • What do you already know about Statistics? • What do you want to know about Statistics? • Make a chart and list 5 things you already know and 5 things you want to know.

3. Basic Terms • Statistics- study of how to collect, organize, analyze, and interpret numerical information from data. • Individuals- people or objects included in the study. • Variable- characteristic of the individual to be measured or observed.

4. Types of Variables • Quantitative- has a value or numerical measurement for which operations such as addition or averaging make sense. • Qualitative- describes an individual by placing the individual into a category or group. • Come up with 3 examples of quantitative and qualitative variables in your groups.

5. Data Source • Population- the data from EVERY individual of interest. • Parameter- numerical measure that describes an aspect of a population. • Sample- the data from ONLY SOME of the individuals of interest. • Statistic- numerical measure that describes an aspect of a sample.

6. Population vs Sample • Which type of data source is usually used? Why? • Give an example of a population statistic. • Do you want similar characteristics of the individuals when taking a sample? Explain why?

7. Population vs. Sample • Pineapples are being harvested to do an experiment. • If all of the pineapples are included in the data, then we have a __________. The average weight of all the pineapples is a ____________. • If only some of the pineapples are included in the data, then we have a ______________. The pineapples are given a taste rating of “good” is a _____________.

8. Levels of Measurement • Nominal- data that consists of names, labels, or categories. • Ordinal- data that can be arranged in order. • Come up with examples of nominal and ordinal data in your groups.

9. Guided Exercises • Discuss in your groups Guided Exercises 1 and 2. • Refer to pg 6 #1 a-e. • Refer to pg 8 #2 a, e-g.

10. 1.1 Homework • Pg 10 #1, 3, 5-8, 9cd, 10acf, 11ad

11. Random Sample Question • In a lottery, people choose six random numbers from 1-100. • Is the number 25 as likely to be selected in the winning group of six numbers as the number 85? • Could all the winning numbers be even? • Could all the winning numbers be odd? • Your friend plays 1, 2, 3, 4, 5, and 6. Could she ever win?

12. 1.2 Random Samples • What does it mean for an experiment to be random? • How would you conduct an experiment randomly? • Why would you want to conduct a random experiment?

13. How to Draw a Random Sample • Number all members of the population. • Use a table, calculator, or computer to select random numbers from the numbers assigned to the population members. • Create the sample by using population members with numbers corresponding to those randomly selected.

14. Simple Random Sample • n measurements from a population is a subset of the population selected in a manner such that every sample of size n from the population has an equal chance of being selected. • Everything has an equally likely chance of being selected. • Random-Number Table: Pg A-9

15. Sampling Techniques • Random- Use a simple random sample from the entire population. • Stratified- Divide the entire population into distinct subgroups called strata. The strata are based on a specific characteristic such as age, income, education level, and so on. All members of a stratum share the specific characteristics. Draw random samples from each stratum. • Systematic- Number all members of the population sequentially. Then, from a starting point selected at random, include every kth member of the population in the sample.

16. Sampling Techniques • Cluster- Divide the entire population into pre-existing segments or clusters. The clusters are often geographic. Make a random selection of clusters. Include every member of each selected cluster in the sample. • Multistage- Use a variety of sampling methods to create successively smaller groups at each stage. The final sample consists of clusters. • Convenience- Create a sample by using data from the population members that are readily available.

17. Sampling Techniques • Refer to page 19 #15 or 16. • Discuss in your groups what type of sampling technique your groups letter is. Be prepared to explain why.

18. Answer the following questions:* • 1. Do you feel that Norwin School District should build an aquarium? • 2. Do you go to the movies often? • 3. Do you like to read? • 4. Do you think it is appropriate for students to use their phones in school? • 5. Do you want to go to college?

19. Now answer these questions:* • 1. Do you feel that Norwin School District should cut the lunch choices to build an aquarium? • 2. Do you go to the movies once a week? • 3. Do you read more than 5 books a year? • 4. Do you think it is inappropriate for students to not use their phones in school? • 5. Is it your desire to advance your educational knowledge by attending a university for four years?

20. 1.3 Introduction to Experimental Design • Observational Study- observations and measurements of individuals are conducted in a way that doesn’t change the response or the variable being measured. • Experiment- a treatment is deliberately imposed on the individuals in order to observe a possible change in the response or variable being measured.

21. More Vocab • Placebo Effect- occurs when a subject receives no treatment but believes he or she is in fact receiving treatment and responds favorably. • Control Group- receives a dummy treatment, enabling the researchers to control for the placebo effect.

22. Variables • Lurking- no data has been collected but nevertheless has influence on other variables in the study. • Two variables: amount of gas and time it takes to get to school • Example: level of traffic • Confounded- effects of one cannot be distinguished from the effects of the other. • Several variables: IQ, difficulty of courses, amount of study time, GPA • Example: less study time takes easier classes

23. Confounding Variables • What would be some confounding variables in the following experiments: • 1. You want to see if students from suburban schools and inner city schools have the same average test score. • 2. Cookie vs Cream Oreo poll online. • 3. Polling students in high school on whether or not they cheat.

24. Survey Project*** • While I pass out the Survey Project, read over Page 20: Basic Guidelines for Planning a Statistical Test and Page 24: Some Potential Pitfalls of a Survey. • Then, take a few minutes to read over the Survey Project.

25. Homework* • You may work in groups of 3 with groups of your choosing. • You do not have to do Section 1.3 Homework. • DO NOT start answering the Guiding Questions yet. Just read over them. You will answer them AFTER you conduct the survey. • For tomorrow, you must think of possible questions to put on your surveys.

26. Timeline* • Monday: Finish 1.3 & begin Survey Project. • HW: Come up with a draft of your Surveys. • Tuesday: Complete Draft of Surveys. Trade Surveys with other groups. Finalize Surveys. If you want copies made they must be turned in by the end of class. Pick them up before homeroom tomorrow. • HW: Conduct survey and collect data. • Wednesday: Answer Guiding Questions and Reflection Questions. Start discussion/ presentations. • Thursday: Finish discussion/presentations. Individually complete Survey Review. • HW: Read Section 2.1 & 2.1 Reading Guide.