Copyright © 2014 Pearson Education. All rights reserved. 1.2-1 1.2 Sampling LEARNING GOAL Understand the importance of choosing a representative sample.

Slides:

Advertisements

Similar presentations

+ The Practice of Statistics, 4 th edition – For AP* STARNES, YATES, MOORE Chapter 4: Designing Studies Section 4.1 Samples and Surveys.

Advertisements

MBF3C Lesson #1: Sampling Types and Techniques

* Students will be able to identify populations and samples. * Students will be able to analyze surveys to see if there is bias. * Students will be able.

Slide Slide 1 Copyright © 2007 Pearson Education, Inc Publishing as Pearson Addison-Wesley. Created by Tom Wegleitner, Centreville, Virginia Edited by.

Sampling Prepared by Dr. Manal Moussa. Sampling Prepared by Dr. Manal Moussa.

Chapter 12 Sample Surveys

Section 5.1. Observational Study vs. Experiment  In an observational study, we observe individuals and measure variables of interest but do not attempt.

Copyright ©2005 Brooks/Cole, a division of Thomson Learning, Inc. How to Get a Good Sample Chapter 4.

Copyright © 2011 Pearson Education, Inc. Samples and Surveys Chapter 13.

Statistics Statistics is the art and science of gathering, analyzing, and making inferences (predictions) from numerical information, data, obtained in.

COLLECTING QUANTITATIVE DATA: Sampling and Data collection

Created by Tom Wegleitner, Centreville, Virginia Section 1-4 Design of Experiments.

McGraw-Hill/Irwin McGraw-Hill/Irwin Copyright © 2009 by The McGraw-Hill Companies, Inc. All rights reserved.

Section Copyright © 2014, 2012, 2010 Pearson Education, Inc. Lecture Slides Elementary Statistics Twelfth Edition and the Triola Statistics Series.

Created by Tom Wegleitner, Centreville, Virginia Section 1-4 Design of Experiments.

The 6 Sample Survey Methods September 26, So far, we have discussed two BAD methods… 1. Voluntary Response Method People who respond usually have.

Surveys and Questionnaires Government agencies, news organizations, and marketing companies often conduct surveys. The results can be factual or subjective.

Section 1.2 ~ Sampling Introduction to Probability and Statistics Ms. Young.

Copyright (C) 2002 Houghton Mifflin Company. All rights reserved. 1 Understandable Statistics Seventh Edition By Brase and Brase Prepared by: Lynn Smith.

Copyright © 2015, 2011, 2008 Pearson Education, Inc. Chapter 5, Unit A, Slide 1 Statistical Reasoning 5.

11.4 Collecting Data and Circle graphs E S: Gather and Organize Information 1.) What percent of the budget is spent on rent? 2.) How much money do the.

Section Copyright © 2014, 2012, 2010 Pearson Education, Inc. Chapter 1 Introduction to Statistics 1-4/1.5Collecting Sample Data.

Under the Guidance of Dr. ADITHYA KUMARI H. Associate Professor DOS in Library and Information Science University of Mysore Mysore By Poornima Research.

Excursions in Modern Mathematics, 7e: Copyright © 2010 Pearson Education, Inc. 13 Collecting Statistical Data 13.1The Population 13.2Sampling.

Population vs. Sample The entire group of individuals that we want information about is called the population. A sample is a part of the population that.

Slide 1 Copyright © 2004 Pearson Education, Inc. Misuses of Statistics  Bad Samples  Small Samples  Misleading Graphs  Pictographs  Distorted Percentages.

Section 1.2 Random Samples 1 Larson/Farber 4th ed.

Copyright © 2014 Pearson Education. All rights reserved Sampling LEARNING GOAL Understand the importance of choosing a representative sample.

Section Copyright © 2014, 2012, 2010 Pearson Education, Inc. Section 1.4 Collecting Sample Data  If sample data are not collected in an appropriate.

Probability Samples Definition: A sample in which the probability that any particular member of the population will be included is known.

Copyright (C) 2002 Houghton Mifflin Company. All rights reserved. 1 Methods of Producing Data Sampling: drawing subsets from the population Experimentation:

Copyright © 2010, 2007, 2004 Pearson Education, Inc. All Rights Reserved. Section 1-5 Collecting Sample Data.

Part III – Gathering Data

Chapter Eleven Sampling: Design and Procedures Copyright © 2010 Pearson Education, Inc

Sampling Techniques Governments, companies, and news agencies often want to know the public’s opinion on pertinent questions. Elections offer an excellent.

A sample is a small number of individuals representing a larger group.

Copyright © 2008 Pearson Education, Inc.. Slide 1-2 Chapter 1 The Nature of Statistics Section 1.3 Other Sampling Designs.

Lecture 1 Stat Applications, Types of Data And Statistical Inference.

SAMPLING TECHNIQUES LECTURE - 2 GE 608 Experimental Methods and Analysis Oct 28, 2015 Muharrum 14, 1437.

Statistical Reasoning

Chapter 5 Sampling: good and bad methods AP Standards Producing Data: IIB4.

2-1 Sample Design. Sample Subset of a larger population Population Any complete group People Sales people Stores Students Teachers.

I can identify the difference between the population and a sample I can name and describe sampling designs I can name and describe types of bias I can.

Design of Experiments & Sampling Techniques.

Data Collection and Experimental Design. Data Collection Methods 1. Observational study 2. Experiment 3. Simulation 4. Survey.

Data Collection and Sampling Techniques.   Data can be collected in a variety of ways. One of the most common methods is through the use of surveys.

HAWKES LEARNING Students Count. Success Matters. Copyright © 2015 by Hawkes Learning/Quant Systems, Inc. All rights reserved. Section 8.1 Collecting Data.

SECTION 1.1 SAMPLING. Objectives 1. Construct a simple random sample 2. Determine when samples of convenience are acceptable 3. Describe stratified sampling,

Chapter 3 Sampling Techniques. Chapter 3 – Sampling Techniques When conducting a survey, it is important to choose the right questions to ask and to select.

1 STAT 500 – Statistics for Managers STAT 500 Statistics for Managers.

Chapter 12 Vocabulary. Matching: any attempt to force a sample to resemble specified attributed of the population Population Parameter: a numerically.

Chapter 2 Lesson 2.2b Collecting Data Sensibly 2.2: Sampling.

Statistics Definitions Part 2. Representative Sample For a sample to be representative of a population, it must possess the same characteristics as the.

Copyright © 2014, 2011 Pearson Education, Inc. 1 Chapter 13 Samples and Surveys.

Sampling Chapter 5. Introduction Sampling The process of drawing a number of individual cases from a larger population A way to learn about a larger population.

Copyright © 2016 The McGraw-Hill Companies, Inc. Permission required for reproduction or display. S AMPLING Section 1.1.

Copyright © 2009 Pearson Education, Inc.

Chapter 12 Sample Surveys.

Statistics Section 1.2 Identify different methods for selecting a sample Simulate a random process Review: quantitative and qualitative variables, population.

Sampling: Design and Procedures

Sampling: Design and Procedures

1.2 Sampling LEARNING GOAL

Introduction to Statistics

1.2 Sampling LEARNING GOAL

Fundamentals of Statistics

Random Samples Skill 03.

Chapter 4: Designing Studies

Random Samples Section 1.3.

EQ: What is a “random sample”?

Sampling Methods and the Central Limit Theorem

Presentation transcript:

Copyright © 2014 Pearson Education. All rights reserved Sampling LEARNING GOAL Understand the importance of choosing a representative sample and become familiar with several common methods of sampling.

Copyright © 2014 Pearson Education. All rights reserved Slide Definition A _____________is the collection of data from every member of a population. Definition A _________________is a sample in which the relevant characteristics of the sample members are generally the same as the characteristics of the population.

Copyright © 2014 Pearson Education. All rights reserved Slide EXAMPLE 1 A Representative Sample for Heights Suppose you want to determine the mean height of all students at your school. Which is more likely to be a representative sample for this study: the men’s basketball team or the students in your statistics class?

Copyright © 2014 Pearson Education. All rights reserved Slide Bias Definition A statistical study suffers from ____________if its design or conduct tends to favor certain results.

Copyright © 2014 Pearson Education. All rights reserved Slide EXAMPLE 2 Why Use Nielsen? Nielsen Media Research earns money by charging television stations and networks for its services. For example, NBC pays Nielsen to provide ratings for its television shows. Why doesn’t NBC simply do its own ratings, instead of paying a company like Nielsen to do them?

Copyright © 2014 Pearson Education. All rights reserved Slide Sampling Methods Simple Random Samples A _______________is one in which every member of the population has an equal chance of being selected to be part of the sample. With __________________every possible sample of a particular size has an equal chance of being selected.

Copyright © 2014 Pearson Education. All rights reserved Slide EXAMPLE 3 Telephone Book Sampling You want to conduct an opinion poll in which the population as all the residents in a town. Could you choose a simple random sample by selecting names from the local telephone book?

Copyright © 2014 Pearson Education. All rights reserved Slide Sampling Methods Simple Random Samples Systematic Sampling A type of sampling in which we use a system such as choosing every 50 th member of a population.

Copyright © 2014 Pearson Education. All rights reserved Slide EXAMPLE 5 When Systematic Sampling Fails You are conducting a survey of students in a co-ed dormitory in which males are assigned to odd-numbered rooms and females are assigned to even-numbered rooms. Can you obtain a representative sample when you choose every 10 th room?

Copyright © 2014 Pearson Education. All rights reserved Slide Sampling Methods Simple Random Samples Systematic Sampling Convenience Samples The sample is chosen for convenience rather than by a more sophisticated procedure.

Copyright © 2014 Pearson Education. All rights reserved Slide EXAMPLE 6 Salsa Taste Test A supermarket wants to decide whether to carry a new brand of salsa, so it offers free tastes at a stand in the store and asks people what they think. What type of sampling is being used? Is the sample likely to be representative of the population of all shoppers?

Copyright © 2014 Pearson Education. All rights reserved Slide Sampling Methods Simple Random Samples Systematic Sampling Convenience Samples Cluster Samples Cluster sampling involves the selection of all members in randomly selected groups, or clusters.

Copyright © 2014 Pearson Education. All rights reserved Slide EXAMPLE 7 Gasoline Prices You want to know the mean price of gasoline at gas stations located within a mile of rental car locations at airports. Explain who you might use cluster sampling in this case.

Copyright © 2014 Pearson Education. All rights reserved Slide Sampling Methods Simple Random Samples Systematic Sampling Convenience Samples Cluster Samples Stratified Samples Stratified sampling involves randomly selecting members from each stratum.

Copyright © 2014 Pearson Education. All rights reserved Slide EXAMPLE 8 Unemployment Data The U.S. Labor Department surveys 60,000 households each month to copile its unemployment reprot. To select these households, the Department first groups cities and counties into about 2000 geographic areas. It then ramdomly selects households to survey within these geographic areas. How is this an example of stratified sampling? What are the strata? Why is stratified sampling important in this case?

Copyright © 2014 Pearson Education. All rights reserved Slide Summary of Sampling Methods Keep in mind the following three key ideas: A study can be successful only if the sample is representative of the population. A biased sample is unlikely to be a representative sample. Even a well-chosen sample may still turn out to be unrepresentative just because of bad luck in the actual drawing of the sample.

Copyright © 2014 Pearson Education. All rights reserved Slide Simple Random Sampling: We choose a sample of items in such a way that every sample of the same size has an equal chance of being selected. Every sample of the same size has an equal chance of being selected. Computers are often used to generate random numbers.

Copyright © 2014 Pearson Education. All rights reserved Slide Systematic Sampling : We use a simple system to choose the sample, such as selecting every 10th or every 50th member of the population. Select every kth member.

Copyright © 2014 Pearson Education. All rights reserved Slide Convenience Sampling : We use a sample that happens to be convenient to select. Use results that are readily available.

Copyright © 2014 Pearson Education. All rights reserved Slide Cluster Sampling : We first divide the population into groups, or clusters, and select some of these clusters at random. We then obtain the sample by choosing all the members within each of the selected clusters. Divide the population into clusters, randomly select some of those clusters, then choose all members of the selected clusters.

Copyright © 2014 Pearson Education. All rights reserved Slide Stratified Sampling : We use this method when we are concerned about differences among subgroups, or strata, within a population. We first identify the strata and then draw a random sample within each stratum. The total sample consists of all the samples from the individual strata. Partition the population into at least two strata, then draw a sample from each.