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# MTH120_Chapter1

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### MTH120_Chapter1

1. 1. 1-1 Chapter One What is Statistics?GOALSWhen you have completed this chapter, you will be able to:ONEUnderstand why we study statistics.TWOExplain what is meant by descriptive statistics and inferential statistics.THREEDistinguish between a qualitative variable and a quantitative variable.FOURDistinguish between a discrete variable and a continuous variable. FIVE Distinguish among the nominal, ordinal, interval, and ratio levels of measurement. SIX Define the terms mutually exclusive and exhaustive.McGraw-Hill/Irwin Copyright © 2002 by The McGraw-Hill Companies, Inc. All rights reserved.
2. 2. 1-2 What is Meant by Statistics? Statistics is the science of collecting, organizing, presenting, analyzing, and interpreting numerical data to assist in making more effective decisions.McGraw-Hill/Irwin Copyright © 2002 by The McGraw-Hill Companies, Inc. All rights reserved.
3. 3. 1-3 Who Uses Statistics? Statistical techniques are used extensively by marketing, accounting, quality control, consumers, professional sports people, hospital administrators, educators, politicians, physicians, etc...McGraw-Hill/Irwin Copyright © 2002 by The McGraw-Hill Companies, Inc. All rights reserved.
4. 4. 1-4 Types of Statistics Descriptive Statistics: Methods of organizing, summarizing, and presenting data in an informative way. EXAMPLE 1: A Gallup poll found that 49% of the people in a survey knew the name of the first book of the Bible. The statistic 49 describes the number out of every 100 persons who knew the answer. EXAMPLE 2: According to Consumer Reports, General Electric washing machine owners reported 9 problems per 100 machines during 2001. The statistic 9 describes the number of problems out of every 100 machines.McGraw-Hill/Irwin Copyright © 2002 by The McGraw-Hill Companies, Inc. All rights reserved.
5. 5. 1-5 Types of Statistics Inferential Statistics: A decision, estimate, prediction, or generalization about a population, based on a sample. A population is a collection of all possible individuals, objects, or measurements of interest. A sample is a portion, or part, of the population of interestMcGraw-Hill/Irwin Copyright © 2002 by The McGraw-Hill Companies, Inc. All rights reserved.
6. 6. 1-6 Types of Statistics (examples of inferential statistics) EXAMPLE 1: TV networks constantly monitor the popularity of their programs by hiring Nielsen and other organizations to sample the preferences of TV viewers.EXAMPLE 2: The accounting department of a largefirm will select a sample of the invoices to check foraccuracy for all the invoices of the company.EXAMPLE 3: Wine tasters sip a few drops of wine tomake a decision with respect to all the wine waiting tobe released for sale.McGraw-Hill/Irwin Copyright © 2002 by The McGraw-Hill Companies, Inc. All rights reserved.
7. 7. 1-7 Types of Variables For a Qualitative or Attribute variable the characteristic being studied is nonnumeric. EXAMPLES: Gender, religious affiliation, type of automobile owned, state of birth, eye color are examples.McGraw-Hill/Irwin Copyright © 2002 by The McGraw-Hill Companies, Inc. All rights reserved.
8. 8. 1-8 Types of Variables In a Quantitative variable information is reported numerically. EXAMPLES: balance in your checking account, minutes remaining in class, or number of children in a family.McGraw-Hill/Irwin Copyright © 2002 by The McGraw-Hill Companies, Inc. All rights reserved.
9. 9. 1-9 Types of Variables Quantitative variables can be classified as either discrete or continuous. Discrete variables: can only assume certain values and there are usually “gaps” between values. EXAMPLE: the number of bedrooms in a house, or the number of hammers sold at the local Home Depot (1,2,3,…,etc).McGraw-Hill/Irwin Copyright © 2002 by The McGraw-Hill Companies, Inc. All rights reserved.
10. 10. 1-10 Types of Variables A continuous variable can assume any value within a specified range. The pressure in a tire, the weight of a pork chop, or the height of students in a class.McGraw-Hill/Irwin Copyright © 2002 by The McGraw-Hill Companies, Inc. All rights reserved.
11. 11. 1-11 Summary of Types of Variables D ATA Q u a lit a t iv e o r a t t r ib u t e Q u a n t it a t iv e o r n u m e r ic a l (ty p e o f c a r o w n e d ) d is c r e t e c o n t in u o u s ( n u m b e r o f c h ild r e n ) ( t im e t a k e n fo r a n e x a m )McGraw-Hill/Irwin Copyright © 2002 by The McGraw-Hill Companies, Inc. All rights reserved.
12. 12. 1-12 Levels of Measurement There are four levels of data. Nominal level: Data that is classified into categories and cannot be arranged in any particular order. EXAMPLES: eye color, gender, religious affiliation.McGraw-Hill/Irwin Copyright © 2002 by The McGraw-Hill Companies, Inc. All rights reserved.
13. 13. 1-13 Levels of Measurement Mutually exclusive: An individual, object, or measurement is included in only one category. Exhaustive: Each individual, object, or measurement must appear in one of the categories.McGraw-Hill/Irwin Copyright © 2002 by The McGraw-Hill Companies, Inc. All rights reserved.
14. 14. 1-14 Levels of Measurement Ordinal level: involves data arranged in some order, but the differences between data values cannot be determined or are meaningless. EXAMPLE: During a taste test of 4 soft drinks, Mellow Yellow was ranked number 1, Sprite number 2, Seven-up number 3, and Orange Crush number 4.McGraw-Hill/Irwin Copyright © 2002 by The McGraw-Hill Companies, Inc. All rights reserved.
15. 15. 1-15 Levels of Measurement Interval level: similar to the ordinal level, with the additional property that meaningful amounts of differences between data values can be determined. There is no natural zero point. EXAMPLE: Temperature on the Fahrenheit scale.McGraw-Hill/Irwin Copyright © 2002 by The McGraw-Hill Companies, Inc. All rights reserved.
16. 16. 1-16 Levels of Measurement Ratio level: the interval level with an inherent zero starting point. Differences and ratios are meaningful for this level of measurement. EXAMPLES: Monthly income of surgeons, or distance traveled by manufacturer’s representatives per month.McGraw-Hill/Irwin Copyright © 2002 by The McGraw-Hill Companies, Inc. All rights reserved.