Sect.1-1 An Over view of Statistics Objective: SWBAT learn the definition of Statistics (b) distinguish between a population and a sample, A parameter and a statistic (C) Distinguish between descriptive statistics and inferential statistics.

Questions to consider ( A) What is Statistics? (B) Why should I study Statistics? (C ) How can Statistics help me in my profession?

Definitions Data Consists of information coming from observations , counts, measurements, or responses. Statistics: Is the science of collecting , organizing, analyzing and Interpreting data in order to make a decision. A population: is the collection of all outcomes ,responses, measurements, or counts that are of interest. A Sample is a subset of a population.

Examples Identifying Data Sets: In a recent survey 3002 adults in the United States were asked if they read news on the internet at least once a week. Six hundred of the adults said Yes. Identify the population and the sample. Describe the data set. The population consists of the responses of all the adults in the United States. And the Sample consists of the 3002 adults in the United States. The data set consists of 600 yes’s and 2402 no’s.

Venn Diagram Responses of adults in the Survey (Sample. ) Responses of all adults in the United States (population. ) Responses of adults in the Survey (Sample. ) 600 yes’s 2402 No’s

Try this Yourself The U.S. Department of Energy conducts surveys of 800 gasoline stations to determine the average price per gallon of regular gasoline. On May 24,2001 the average price was $1.713 per gallon. Identify the population and the Sample.

Answer The population consists of the prices per gallon of all stations in the United States. The Sample consists of the prices per gallon of regular gas at the 800 surveyed stations. The data sets consists of the 800 prices.

Definitions A parameter Is a numerical description of a population characteristic. A statistic is a numerical description of a sample characteristic.

Examples 1.)A recent survey of a sample of MBA’s reported that the average starting salary for an MBA is less than $65,000. 2.) Starting salaries for the 667 MBA graduates from the University of Chicago Graduate School of Business increased 8.5% from the previous year. 3.) In a random check of retail stores The Food and Drug Administration found that 34% of the stores were not storing fish at the proper temperature.

Solution 1.) because the numerical measure of $65,000 is based on a subset of the population it is a sample statistic. 2.)Because the numerical measure of 8.5% is based on all 667 graduates starting salaries it is a population statistic. 3.) Because the numerical measure of34% is based on a subset of the population it is a sample statistic.

Try This Yourself In 2001 major league baseball teams spent a total of $1,968,088,814 on players salaries. Does this numerical value represent a population parameter or a sample statistic? a.) It is Population b.) It is a parameter.

Branches of Statistics Definition Descriptive Statistics: is the branch of statistics that involves the organization ,summarization , and display of data. Inferential Statistics: is the branch of statistics that involves using a sample to draw conclusions about a population. A basic tool in the study of Inferential statistics is Probability.

Example A large sample of men aged 48 were studied for 18 years. For unmarried men 60% to 70% were alive at 65. For married men 90% were alive at 65. Which part represents descriptive Statistics? What conclusions might be drawn from this study using inferential Statistics? Solution Descriptive Statistics involves statements such as For unmarried men 60% to 70% were alive at 65. For married men 90% were alive at 65 A possible inference that might be drawn from this study is that being married is associated with a longer life for men.

Example In a sample of Wall Street analysts the percent who incorrectly forecasted high-tech earnings in a recent year was 44%. Solution The part of the study that represents the descriptive branch of statistics involves the statement “ The percent of Wall Street analysts who incorrectly forecasted high-tech earnings in a recent year was 44%”. A possible inference drawn from the study is that the stock market is difficult to forecast even for professionals.

Homework Pgs. 6-7 1-6,9-11, 13-15,17-19,21-24 and 29

An Overview of Statistics 5/21/2019 Section 1.1 An Overview of Statistics After you see the slides for each section, do the Try It Yourself problems in your text for that section to see if you understood the material. Then, do the assigned problems for that section.

Introduction to Statistics 5/21/2019 Introduction to Statistics As you view these slides be sure to have paper, pencil, a calculator and your text handy. Click to advance to the slide show.

What Is Statistics? 5/21/2019 Statistics is the science of collecting, organizing, analyzing, and interpreting data in order to make decisions. Most students have enrolled in statistics because it is required. Most have no idea of what statistics is about. In Chapter 1 you’ll learn about different types of data (pieces of information) and methods of collecting data.

Important Terms Population Sample The collection of all responses, 5/21/2019 Important Terms Population The collection of all responses, measurements, or counts that are of interest. Sample A portion or subset of the population. To learn about any subject, it is important that you know the language of that subject. Here are some commonly used terms. Although a group of people working for a specific computer software company is shown, the population actually consists of the data set. Each piece of data is represented by an x. The population could be the type of car they each drive, their seniority rank, the year they were born or their gross income in 2002. How do you know if a data set is a population or a sample? This depends on the context of the problem. If you are doing a study that only concerns workers of this company then use the people in the company to produce the population of values. On the other hand, if your study involves all workers in computer software companies in California, then you would use all the people at the top as a sample (called a cluster sample) of the population. Each population has many many possible samples. Population of values may not come from people at all. If you are interested in the miles per gallon of all Honda Civics then the population would be measured from the cars.

Important Terms Parameter Statistic 5/21/2019 Important Terms Parameter A number that describes a population characteristic. Average gross income of all people in the United States in 2002. Statistic A number that describes a sample characteristic. These terms are used throughout the course. The arrows at the end, emphasize the connection between population parameter and sample statistic. You will also later learn that this type of sample is called a cluster sample because it comes from intact units in the population. 2002 gross income of people from a sample of three states.

Two Branches of Statistics 5/21/2019 Two Branches of Statistics Descriptive Statistics Involves organizing, summarizing, and displaying data. Inferential Statistics Involves using sample data to draw conclusions about a population. Descriptive statistics involve graphs creating numerical summaries. Techniques of descriptive statistics will be covered in the next chapter. Inferential statistics will be introduced in later chapters.