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1-1




   Chapter

            One




McGraw-Hill/Irwin   © 2005 The McGraw-Hill Companies, Inc., All Rights Reserved.
1-2


                   Chapter One
                   What is Statistics?
GOALS
When you have completed this chapter, you will be able to:
ONE
Understand why we study statistics.
TWO
Explain what is meant by descriptive statistics and inferential statistics.
THREE
Distinguish between a qualitative variable and a quantitative variable.
FOUR
Distinguish 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.                          Goals
1-3




    Statistics is the science
    of collecting, organizing,
    presenting, analyzing,
    and interpreting
    numerical data to assist
    in making more
    effective decisions.


µ            Σ                   β
    λ                σ
                          What is Meant by Statistics?
1-4




Statistical techniques are
used extensively by
marketing, accounting,
quality control,
consumers, professional
sports people, hospital
administrators,
educators, politicians,
physicians, and many
others.


                             Who Uses Statistics?
1-5



Descriptive Statistics: Methods of organizing,
summarizing, and presenting data in an informative way.
EXAMPLE 1: A               EXAMPLE 2: According
Gallup poll found that     to Consumer Reports,
49% of the people in a     General Electric washing
survey knew the name       machine owners reported
of the first book of the   9 problems per 100
Bible. The statistic 49    machines during 2001.
describes the number       The statistic 9 describes
out of every 100           the number of problems
persons who knew the       out of every 100 machines.
answer.
                                      Types of Statistics
1-6


Inferential Statistics: A decision, estimate,
prediction, or generalization about a population,
based on a sample.

A Population                         A Sample is a
is a Collection                      portion, or part,
of all possible                      of the population
individuals,                         of interest
objects, or
measurements of
interest.


                                    Types of Statistics
1-7

Example 1: TV            Example 2: Wine
networks constantly      tasters sip a few drops
monitor the              of wine to make a
popularity of their      decision with respect
programs by hiring       to all the wine waiting
Nielsen and other        to be released for sale.
organizations to
sample the            Example 3: The accounting
preferences of TV     department of a large firm will
viewers.              select a sample of the invoices to
                      check for accuracy for all the
                      invoices of the company.
     #1
                                       Types of Statistics
                                  (examples of inferential statistics)
1-8



For a Qualitative or Attribute Variable the
characteristic being studied is nonnumeric.
   G en der
                   E ye
                  C o lo r


                 S ta te of
  T ype of car     B irt h


                                  Types of Variables
1-9




   In a Quantitative Variable information is
              reported numerically.


        Balance in your checking account


     Minutes remaining in class


Number of children in a family

                                     Types of Variables
1-10


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).

                                        Types of Variables
1-11


    A Continuous Variable can assume
      any value within a specified range.


The pressure in a tire


     The weight of a pork chop


               The height of students in a class.


                                         Types of Variables
1-12




                                                   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 i t a t i v 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 )




                                                                    Summary of Types of Variables
1-13




There are four levels of
         data
      Nominal
      Ordinal
      Interval
       Ratio


                      Levels of Measurement
1-14



Nominal level        G en der
Data that is
classified into
categories and
cannot be arranged               E ye
in any particular               C o lo r
order.




                                  Nominal data
1-15



    Nominal level variables must be:

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.
                                  Levels of Measurement
1-16


Ordinal level: involves data arranged in some
order, but the differences between data values cannot
be determined or are meaningless.

During a taste test
of 4 soft drinks,                         4
                               2
Coca Cola was
ranked number 1,
Dr. Pepper number                               3
2, Pepsi number 3,
                                      1
and Root Beer
number 4.
                                          Levels of Measurement
1-17



                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.



                         Temperature on
                         the Fahrenheit
                         scale.


                                         Levels of Measurement
1-18


Ratio level: the interval level with an inherent
zero starting point. Differences and ratios are
meaningful for this level of measurement.

  M ile s t ra v e le d b y s a le s      M o n t h ly in c o m e
re p re s e n t a t iv e in a m o n t h
                                            o f su rg eo n s




                                                         Levels of Measurement

More Related Content

Chapter 01 power point

  • 1. 1-1 Chapter One McGraw-Hill/Irwin © 2005 The McGraw-Hill Companies, Inc., All Rights Reserved.
  • 2. 1-2 Chapter One What is Statistics? GOALS When you have completed this chapter, you will be able to: ONE Understand why we study statistics. TWO Explain what is meant by descriptive statistics and inferential statistics. THREE Distinguish between a qualitative variable and a quantitative variable. FOUR Distinguish 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. Goals
  • 3. 1-3 Statistics is the science of collecting, organizing, presenting, analyzing, and interpreting numerical data to assist in making more effective decisions. µ Σ β λ σ What is Meant by Statistics?
  • 4. 1-4 Statistical techniques are used extensively by marketing, accounting, quality control, consumers, professional sports people, hospital administrators, educators, politicians, physicians, and many others. Who Uses Statistics?
  • 5. 1-5 Descriptive Statistics: Methods of organizing, summarizing, and presenting data in an informative way. EXAMPLE 1: A EXAMPLE 2: According Gallup poll found that to Consumer Reports, 49% of the people in a General Electric washing survey knew the name machine owners reported of the first book of the 9 problems per 100 Bible. The statistic 49 machines during 2001. describes the number The statistic 9 describes out of every 100 the number of problems persons who knew the out of every 100 machines. answer. Types of Statistics
  • 6. 1-6 Inferential Statistics: A decision, estimate, prediction, or generalization about a population, based on a sample. A Population A Sample is a is a Collection portion, or part, of all possible of the population individuals, of interest objects, or measurements of interest. Types of Statistics
  • 7. 1-7 Example 1: TV Example 2: Wine networks constantly tasters sip a few drops monitor the of wine to make a popularity of their decision with respect programs by hiring to all the wine waiting Nielsen and other to be released for sale. organizations to sample the Example 3: The accounting preferences of TV department of a large firm will viewers. select a sample of the invoices to check for accuracy for all the invoices of the company. #1 Types of Statistics (examples of inferential statistics)
  • 8. 1-8 For a Qualitative or Attribute Variable the characteristic being studied is nonnumeric. G en der E ye C o lo r S ta te of T ype of car B irt h Types of Variables
  • 9. 1-9 In a Quantitative Variable information is reported numerically. Balance in your checking account Minutes remaining in class Number of children in a family Types of Variables
  • 10. 1-10 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). Types of Variables
  • 11. 1-11 A Continuous Variable can assume any value within a specified range. The pressure in a tire The weight of a pork chop The height of students in a class. Types of Variables
  • 12. 1-12 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 i t a t i v 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 ) Summary of Types of Variables
  • 13. 1-13 There are four levels of data Nominal Ordinal Interval Ratio Levels of Measurement
  • 14. 1-14 Nominal level G en der Data that is classified into categories and cannot be arranged E ye in any particular C o lo r order. Nominal data
  • 15. 1-15 Nominal level variables must be: 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. Levels of Measurement
  • 16. 1-16 Ordinal level: involves data arranged in some order, but the differences between data values cannot be determined or are meaningless. During a taste test of 4 soft drinks, 4 2 Coca Cola was ranked number 1, Dr. Pepper number 3 2, Pepsi number 3, 1 and Root Beer number 4. Levels of Measurement
  • 17. 1-17 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. Temperature on the Fahrenheit scale. Levels of Measurement
  • 18. 1-18 Ratio level: the interval level with an inherent zero starting point. Differences and ratios are meaningful for this level of measurement. M ile s t ra v e le d b y s a le s M o n t h ly in c o m e re p re s e n t a t iv e in a m o n t h o f su rg eo n s Levels of Measurement