1. What is Statistics?
Chapter 1

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Chapter Goals
When you have completed this chapter, you will be able to: 1.
Explain what is meant by statistics. 2.
Identify the role of statistics in the development of knowledge and everyday life. 3.
Explain what is meant by descriptive statistics and inferential statistics. 4.
Distinguish between a qualitative variable and a quantitative variable.
and...

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Chapter Goals 5.
Distinguish between a discrete variable and a continuous variable. 6.
Collect data from published and unpublished sources. 7.
Distinguish among the nominal, ordinal, interval, and ratio levels of measurement. 8.
Identify abuses of statistics.
and...

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Chapter Goals 9.
Gain an overview of the art and science of statistics.
We recommend that you read this chapter at least twice, once at the beginning and once at the end of your course!

5. Statistics? What is Meant by collecting organizing presenting data
…it is the art and science of…
collecting
organizing
presenting data
drawing inferences from a sample of information about an entire population
as well as
predicting and developing policy analysis
What is Meant by
Statistics?

6. Role played
by Statistics
in everyday life

7. Who uses Statistics? Those using Statistical techniques include :
Marketers
Investors
Accountants
Economists
Sports people
Consumers
Statisticians
Hospitals
Quality Controllers
Educators
Politicians
Physicians

8. Who uses Statistics?
Weather
Forecasters

9. Who uses Statistics?
Sports

10. Types of Statistics

11. Methods of… collecting organizing presenting
Types of Statistics
Descriptive
Inferential
Methods of… collecting organizing presenting
and
analyzing data
Science of… making inferences about a population, based on sample information.

12. Identify the following…
C. Wine tasters sip a few drops of wine to make a decision with respect to all the wine waiting to be released for sale.
A. A Gallup poll found that 83% of the people in a survey knew which country won the gold medal in Men’s Hockey in 2002.
B. The accounting department of a firm will select a sample of invoices to check for accuracy of all the invoices of the company.
Descriptive
Inferential

13. The Method of Experimentation
We start off with particular observations from the real world and draw conclusions about the general patterns in the real world!
1. Define the experimental goal or a working hypothesis
2. Design an experiment
3. Collect data
4. Estimate the values/relations
5. Draw inferences
6. Predict and prepare policy analysis
Chapters 8 and 12
Chapters 3 and 4
Chapters 5,7,8 and 9

14. Real World Real World The Method of Experimentation Deductive Method
Inductive Method
Real
World
Statistical Techniques
Definitions & Assumptions
Experimental Design & Data Collection
Rules of Logic
Objective or Working-Hypothesis
Real
World
Implications or Hypotheses

15. Let’s review the steps they would take to prepare the estimate.
A Study
A study was undertaken to estimate the average height of penguins in Antarctica.
Let’s review the steps they would take to prepare the estimate.

16. What Information
do we need?
the POPULATION

17. A population is a collection of all possible individuals, objects, or measurements of interest

18. POPULATION Say, 101 Sample POPULATION
From
POPULATION
Sample
Take a
Say, 101
…which are deemed to be representative of the
POPULATION
What we now need is…

19. Raw Data 101 Sample Take a Measurement for each one in the sample
Record

20. readable and understandable
Goal ?
What
Now
…to put the data
into a
readable and understandable
format!
Displaying Data Results

21. Two methods that can be used to ‘see’
what the data conveys are Tables and Graphs/Charts
More on these in chapter 2…

22. Tables e.g. 101 … are an efficient method of displaying data
and depicting data accurately.
e.g.
101
More on these in chapter 2…

23. Bar Pie Line Scatter Histogram Charts Graphs
More on these in chapter 2…

24. Why take a sample instead of studying every member of the population?
Costs of surveying the entire population may be too large or prohibitive
Destruction of elements during investigation
Accuracy of results
More in chapter 8 …

25. Why Study Statistics?
Data are everywhere
Statistical techniques are used to make many decision that affect our lives
No matter what your future line of work, you will make decisions that involve data. An understanding of statistical methods will help you make these decisions more effectively.

26. Types of
Data

27. a characteristic of a population or sample
Types of Data
A Variable
a characteristic of
a population or sample
that is of interest to us

28. Types of Data Variables
Qualitative
Quantitative
Categorical
Observations
Numerical
Observations

29. Variables Qualitative – or Attribute Female Country of Birth U.K.
Germany
Taiwan
China
India
Japan
Russia
Eye Colour
Blue
Brown
Hazel
Green
Red
GenderMale
Female

30. Variables Quantitative – Numeric Minutes to end of Class55 45 30 5
Number of Two-Door Garages in a Street 10 20 30 40
...
Number of Satisfied Maple Leafs Fans 20 30 40 …
Number of Children in a Family 1 2 3 4 …

31. … can be classified as either
Variables
Quantitative
Numerical
Observations
… can be classified as either
Discrete or
Continuous
Characteristics
… can only assume certain values and there are usually “gaps” between values
Discrete
e.g. - Number of bedrooms in a house
- Number of hammers sold (1,2,3,…etc)

32. Variables Continuous Quantitative … can be classified as either
Numerical
Observations
… can be classified as either
Discrete or
Continuous
Characteristics
… can assume any value within a specified range!
Continuous
e.g. - Pressure in a tire
- Weight of a pork chop
- Height of students in a class

33. Summary of Types of Variables
Data
Qualitative
Categorical
Observations
Quantitative
Numerical
Observations
Discrete
Continuous
(number of children)
(time used for an exam)

34. Collecting Data

35. Sources of Statistical Information
Published Data
Statistical Abstracts
Weather
Sports

36. Sources of Statistical Information
Government of Canada & Provinces
Internet

37. Sources of Statistical Information
International
Organization for Economic Co-operation and Development
IMF

38. Sources of Statistical Information
Commissioned surveys:
To develop information for the survey that they are doing, pollsters often contact the selected ‘sample population’.
For Example…At home, over the telephone, by mail, by , in the street, and at shopping malls!
How to collect data…

39. Levels of
Measurement

40. Nominal
Levels of
Measurement
Ordinal
Interval
Ratio

41. Candy By Colour only Levels of Measurement M & Ms Nominal
Data can only be classified into categories or counted and cannot be arranged in any particular order
M & Ms
Example
Category:
Candy
By Colour only
Classification:
(No natural order)

42. Levels of Measurement M & Ms Nominal Mutually Exclusive:
Example
Mutually Exclusive:
…where an individual, object, or measurement is included in ONLY ONE CATEGORY
Exhaustive:
…where each individual, object, or measurement MUST APPEAR in one of the categories

43. During a taste test of 4 soft drinks:
Levels of
Measurement
Ordinal
…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:
Mello Yello was ranked number……..…. 1.
Sprite number……………………………. 2.
Seven Up number..…………………..…... 3.
Orange Crush number ….……………….4.

44. Levels of Measurement Interval There is no natural zero point
…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 Celsius scale.

45. Distance travelled by manufacturer’s representatives per month
Levels of
Measurement
Ratio
…the Interval Level with an inherent zero starting point.
Differences and ratios are meaningful for this level of measurement.
Examples
Monthly income of surgeons
Distance travelled by manufacturer’s representatives per month

46. Abuses of Statistics

47. “There are three kinds of lies…
Benjamin Disraeli said…
“There are three kinds of lies…
Lies
Damned Lies
&
Objects: Stats_2ProbSample-B.ppt (Probability)
Action Button: Stat Samples_B.ppt (Penguins) for Probability
pen-heights_2Rev.xls (for Penguins)
Statistics!

48. Figures don’t lie.
Liars figure!
Caution

49. … graphs can also be misleading
Caution
As you begin to study statistical methods, you are cautioned to take what you see published as “statistical facts” with a healthy grain of skepticism!
… an average may not be representative of all the data
… graphs can also be misleading
… be sure to study the sampling methods
For Example

50. Caution
Review the following three slides and notice the effect that the different scales have on your interpretation of the pattern between Crime and Unemployment Rates.

51. Unemployment Crime Rate &
Chart 1-11A
3200
3000
2800
2600
2400
2200
2000
(in thousands)
Crime Rate
Unemployment Rate (%)

52. Unemployment Crime Rate &
Chart 1-11B
3000
2500
2000
1500
1000
500
3000
2500
2000
(in thousands)
Crime Rate
1500
1000
500
Unemployment Rate (%)

53. Unemployment Crime Rate &
Chart 1-11C
3200
3000
2800
2600
2400
2200
2000
(in thousands)
Crime Rate
Unemployment Rate (%)

54. Test your learning… Click on… www.mcgrawhill.ca/college/lind
Online Learning Centre
for quizzes
extra content
data sets
searchable glossary
access to Statistics Canada’s E-Stat data
…and much more!

55. This completes Chapter 1.