Please get out materials for notes. Make sure

 Please get out materials for notes.  Make sure

Please get out materials for notes. Make sure to grab a outline at the front desk. 22 23 Introductions/ Expectations Sampling Design SRSs (4.1) 29 Observational Study vs. Experiment (4.2) 5 No School Labor Day 24/25 Sampling Design (4.1) Bias, Random Digits,

Bear Hunt Visual Bias Lab 26 Pep Rally Get Textbooks if needed Federalist Paper activity Assign take-home Quiz 4.1 30 Take-home quiz due Experimental Design (4.2) 31/1 Experimental Design (4.2) Experimental Design WKST 2 Quiz 4.2 Assign Current Event Project

6 Challenges of establishing Causation (4.3) 7/8 FRAPPY! Review Chapter 4 9 Test 1: Chapter 4 Designing Studies The Current Event Project will be due on Tuesday, September 13th. Ch. 4: Designing Studies S EC T I O N 4. 1 S A M P L ES & S URV EY S Samples and Surveys Learning Objectives After this section, you should be able to: IDENTIFY the population and sample in a statistical study. IDENTIFY voluntary response samples and convenience

samples. EXPLAIN how these sampling methods can lead to bias. DESCRIBE how to obtain a random sample using slips of paper, technology, or a table of random digits. DISTINGUISH a simple random sample from a stratified random sample or cluster sample. Give the advantages and disadvantages of each sampling method. EXPLAIN how undercoverage, nonresponse, question wording, and other aspects of a sample survey can lead to The Practice of Statistics, 5th Edition 4 Population, Census, and Sample Population Population -- aa statistical statistical study study is is the the entire entire group group of

of individuals individuals we we want want information information about. about. Census Census -- collects collects data data from from every every individual individual in in the the population. population. Sample Sample -- aa subset subset of of individuals individuals in in the the population population from from which

which we we actually actually collect collect data. data. Population Sample Collect data from a representative Sample... Make an Inference about the Population. Example on P. 210 Identify the population and the sample in each of the following settings: a) A furniture maker buys hardwood in large batches. The supplier is supposed to dry the wood before shipping (wood that isnt dry wont hold its size and shape). The furniture maker chooses five pieces of wood from each batch and tests their moisture content. If any piece exceeds 12% moisture content, the entire batch is sent back.

b) Each week, the Gallup Poll questions a sample of about 1500 adult U.S. residents to determine national opinion on a wide variety of issues. The Idea of a Sample Survey Choosing a Sample Step 1: Define the population we want to describe. Step 2: Say exactly what we want to measure. Sample survey - a study that uses an organized plan to choose a sample that represents some specific population. Step 3: Decide how to choose a sample from the population. How to Sample Badly How can we choose a sample that we can trust to represent the population? Choosing Choosing individuals individuals from from the the population population who who are

are easy easy to to reach reach results results in in aa convenience convenience sample. sample. Convenience samples often produce unrepresentative datawhy? The The design design of of aa statistical statistical study study shows shows bias bias ifif itit would would consistently consistently underestimate underestimate or or consistently consistently overestimate

overestimate the the value value you you want want to to know. know. How to Sample Badly A A voluntary voluntary response response sample sample consists consists of of people people who who choose choose themselves themselves by by responding responding to to aa general

general invitation. invitation. Voluntary Voluntary response response samples samples show show bias bias because because people people with with strong strong opinions opinions (often (often in in the the same same direction) direction) are are most most likely likely to to respond. respond.

AP Exam Tip, P. 212 If youre asked to describe how the design of a study leads to bias, youre expected to do the following: Identify a problem with the design. 2. Explain how this problem would lead to an underestimate or overestimate. 1. Check Your Understanding P. 213 For each of the following situations, identify the sampling method used. Then explain how the sampling method could lead to bias. 1. A farmer brings a juice company several crates of oranges each week. A company inspector looks at 10 oranges from the top of each crate before deciding whether to buy all the oranges. Convenience sampling This could lead to the inspector overestimating the quality of the

oranges if the farmer puts the best oranges on top. Check Your Understanding P. 213 For each of the following situations, identify the sampling method used. Then explain how the sampling method could lead to bias. 2. The ABC program Nightline once asked whether the United Nations should continue to have its headquarters in the U.S.. Viewers were invited to call one telephone number to respond Yes and another for No. There was a charge for calling either number. More than 186,000 callers responded, and 67% said No. Voluntary response sampling those who are happy that the UN has its headquarters in the U.S. already have what they want and so are less likely to respond. The proportion who answered No in the sample is likely to be higher than the true proportion in the U.S. who would answer No. How to Sample Well: Simple Random Sampling

A sample chosen by chance rules out both favoritism by the sampler and self-selection by respondents. Random sampling involves using a chance process to determine which members of a population are included in the sample. A A simple simple random random sample sample (SRS) (SRS) of of size size n n is is chosen chosen in in such such aa way way that that every every group group of of nn individuals individuals in in the the population

population has has an an equal equal chance chance to to be be selected selected as as the the sample. sample. In practice, people use random numbers generated by a computer or calculator to choose samples. If you dont have technology handy, you can use a table of random digits (Table D in book). Homework Due Tuesday P. 229 # 1 9 odd

Recently Viewed Presentations

  • Figurative Language - Meet Mrs. Lefeld

    Figurative Language - Meet Mrs. Lefeld

    Figurative Language Is a tool that an author uses to help the reader visualize (or see) what is happening in a story Idiom-Idioms are sayings that have hidden meanings that don't mean exactly what is stated You better hold your...
  • Political Parties: The Two Party System - Polk School District

    Political Parties: The Two Party System - Polk School District

    Oppose the International Kyoto Treaty (designed to limit air pollution) because it limits economic growth Democrats Consistent government funding of social programs (universal health care, medicare, medicaid, social security, welfare, etc.) Minimum wage Progressive income taxes to pay for increased...
  • Ambulatory CDI - EMMC

    Ambulatory CDI - EMMC

    Critical Care . Infusion/Injection - Nursing. CDI in the Peri-Op Setting. NSQIP . Immediate Post-OP note Audits. Surgical Assist Audits. ... Ambulatory CDI Monthly Overview. July 18,2017 to July 31, 2017. Previous RAF score. Current RAF score. RAF score increase...
  • Using WCOnline to Schedule Collin College OWL Appointments

    Using WCOnline to Schedule Collin College OWL Appointments

    - ASL Lab- Accessing the Online Appointment System ... This time the checkmark will turn RED and the system will readClock Out. ... Essays: Students and their professors receive an email notice from their consultants by midnight of the third...
  • Chapter 14 Wireless LANs 14.1  Copyright  The McGraw-Hill

    Chapter 14 Wireless LANs 14.1 Copyright The McGraw-Hill

    Note Figure 14.11 Use of handshaking to prevent hidden station problem Figure 14.12 Exposed station problem Figure 14.13 Use of handshaking in exposed station problem Table 14.4 Physical layers Figure 14.14 Industrial, scientific, and medical (ISM) band Figure 14.15 Physical...
  • Adhesive Capsulitis

    Adhesive Capsulitis

    "Shrug sign" with GH elevation. Special Tests:4. Neer. Hawkins-Kennedy. Outcome Measures . SS. 90.6-percent of patients reported pain before loss of motion1. ADL's = washing hair, donning/doffing bra, tucking in shirt (men) Consider timing of symptoms and duration.
  • Phonics spelling and grammar!! -

    Phonics spelling and grammar!! -

    National curriculum. Spelling, vocabulary, grammar, punctuation and glossary . The two statutory appendices - on spelling and on vocabulary, grammar and punctuation - give an overview of the specific features that should be included in teaching the programmes of study.Opportunities...
  • video slide - San Jose State University

    video slide - San Jose State University

    Learning Goals for Chapter 36. Looking forward at … how to calculate the intensity at various points in a single-slit diffraction pattern. what happens when coherent light shines on an array of narrow, closely spaced slits.