Chapter Introduction to Statistics 1 1 of 61  2012 Pearson Education, Inc. All rights reserved.

Chapter Outline 1.1 An Overview of Statistics 1.2 Data Classification 1.3 Experimental Design © 2012 Pearson Education, Inc. All rights reserved. 2 of 61

Section 1.1 An Overview of Statistics © 2012 Pearson Education, Inc. All rights reserved. 3 of 61

Section 1.1 Objectives Define statistics Distinguish between a population and a sample Distinguish between a parameter and a statistic Distinguish between descriptive statistics and inferential statistics © 2012 Pearson Education, Inc. All rights reserved. 4 of 61

What is Data? Data Consist of information coming from observations, counts, measurements, or responses. “People who eat three daily servings of whole grains have been shown to reduce their risk of…stroke by 37%.” (Source: Whole Grains Council) “Seventy percent of the 1500 U.S. spinal cord injuries to minors result from vehicle accidents, and 68 percent were not wearing a seatbelt.” (Source: UPI) © 2012 Pearson Education, Inc. All rights reserved. 5 of 61

What is Statistics? Statistics The science of collecting, organizing, analyzing, and interpreting data in order to make decisions. © 2012 Pearson Education, Inc. All rights reserved. 6 of 61

Data Sets Population The collection of all outcomes, responses, measurements, or counts that are of interest. Sample A subset of the population. © 2012 Pearson Education, Inc. All rights reserved. 7 of 61

Example: Identifying Data Sets In a recent survey, 1500 adults in the United States were asked if they thought there was solid evidence for global warming. Eight hundred fifty-five of the adults said yes. Identify the population and the sample. Describe the data set. (Adapted from: Pew Research Center) © 2012 Pearson Education, Inc. All rights reserved. 8 of 61

Solution: Identifying Data Sets Population Sample Data Set © 2012 Pearson Education, Inc. All rights reserved. 9 of 61

Parameter and Statistic P arameter A number that describes a population characteristic. Average age of all people in the United States S tatistic A number that describes a sample characteristic. Average age of people from a sample of three states © 2012 Pearson Education, Inc. All rights reserved. 10 of 61

Example: Distinguish Parameter and Statistic Decide whether the numerical value describes a population parameter or a sample statistic. 1.A recent survey of a sample of college career centers reported that the average starting salary for petroleum engineering majors is $83,121. (Source: National Association of Colleges and Employers) Solution: © 2012 Pearson Education, Inc. All rights reserved. 11 of 61

Example: Distinguish Parameter and Statistic Decide whether the numerical value describes a population parameter or a sample statistic. 2.The 2182 students who accepted admission offers to Northwestern University in 2009 have an average SAT score of (Source: Northwestern University) Solution: © 2012 Pearson Education, Inc. All rights reserved. 12 of 61

Branches of Statistics Descriptive Statistics Involves organizing, summarizing, and displaying data. e.g. Tables, charts, averages Inferential Statistics Involves using sample data to draw conclusions about a population. © 2012 Pearson Education, Inc. All rights reserved. 13 of 61

Example: Descriptive and Inferential Statistics Decide which part of the study represents the descriptive branch of statistics. What conclusions might be drawn from the study using inferential statistics? A large sample of men, aged 48, was studied for 18 years. For unmarried men, approximately 70% were alive at age 65. For married men, 90% were alive at age 65. (Source: The Journal of Family Issues) © 2012 Pearson Education, Inc. All rights reserved. 14 of 61

Solution: Descriptive and Inferential Statistics Descriptive statistics involves statements such as “For unmarried men, approximately 70% were alive at age 65” and “For married men, 90% were alive at 65.” A possible inference drawn from the study is that being married is associated with a longer life for men. © 2012 Pearson Education, Inc. All rights reserved. 15 of 61

Section 1.1 Summary Defined statistics Distinguished between a population and a sample Distinguished between a parameter and a statistic Distinguished between descriptive statistics and inferential statistics © 2012 Pearson Education, Inc. All rights reserved. 16 of 61

Guided Practice – page 6 - # 2,5,9,11-17 odd, odd, 37,41,43 Homework: page 6 # 3,10,12-18 even, 22, even, 36,44