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Measurement with Numbers Scaling: What is a Number?

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Presentation on theme: "Measurement with Numbers Scaling: What is a Number?"— Presentation transcript:

1 Measurement with Numbers Scaling: What is a Number?

2 What is a number? Names and symbols are arbitrary.

3 What is a number? Names and symbols are arbitrary. Four…. IV …. 4….

4 What is a number? Names and symbols are arbitrary.

5

6

7 Numbers that are not numbers….

8 Numbers that are not numbers… Some make the world go around.

9 Measurement: So then? “Rules for assigning numbers to objects
What is a….. Measurement: “Rules for assigning numbers to objects (or concepts) to represent quantities of attributes.”

10 Measurement But to be a true number scale the symbols
must follow some logical and systematic arrangement.

11 Numbers can be assigned using… Scales:
“A scale is the continuum upon which measurements are located.”

12 Zero degrees centigrade….

13 Scales: Likert Scale is a common example.
It is a statement (not a question) followed by five categories of agreement.

14 Scales: Likert Scale Ice cream is good for breakfast.
1. Strongly disagree 2. Disagree 3. Neither agree nor disagree 4. Agree 5. Strongly agree

15 Scales: Likert Scale

16 Scales:

17 Scales: Likert-like

18 Scales: Likert Scale

19 Typically: Opposite adjectives
Scales: Semantic scales: Typically: Opposite adjectives separated by 7 selection points.

20 Scales:

21 Semantic scales:

22

23 Semantic scales:

24 Hybrid Scales:

25 But complex concepts in business may not be easily measured.

26 Harvard professor S.S. Stevens
created numerical scales to measure difficult concepts. S. S. Stevens

27 Steven’s original paper in Science, 103(2684), June 7, 1946.

28

29 Steven’s Scales: 1. Nominal Scales

30 Steven’s Scales: Nominal Scales a. Name

31 Steven’s Scales: Nominal Scales a. Name b. Classify

32 Steven’s Scales: Nominal Scales a. Name b. Classify c. Categorize

33 Steven’s Scales: Nominal Scales a. Name b. Classify c. Categorize

34

35 Why is this 380? Why is this 235?

36 Steven’s Scales: Nominal Scales Ordinal Scales

37 Steven’s Scales: Nominal Scales Ordinal Scales
Does everything a nominal scales does. Ranks objects or concepts by some characteristic.

38 Steven’s Scales: Nominal Scales Ordinal Scales Interval scales

39 Steven’s Scales: Nominal Scales Ordinal Scales Interval scales
Does everything an ordinal scale does. The Interval is now meaningful.

40 Steven’s Scales: Nominal Scales Ordinal Scales Interval scales
Ratio scales

41 Steven’s Scales: Nominal Scales Ordinal Scales Interval scales
Ratio scales Has all the characteristics of all other scales, but it also has meaningful ratios. It has a true zero.

42 Good source:

43 Steven’s Scales: Nominal Scales Ordinal Scales X = f(x)
Interval scales X = kx + c Ratio scales X = kx

44 Which scale to use? Amount of information needed

45 Which scale to use? Amount of information needed
Each higher scale carries more information than the one before it.

46 Which scale to use? Amount of information needed
Characteristics of stimulus or concept

47 Which scale to use? Amount of information needed
Characteristics of stimulus or concept Application context

48 Which scale to use? Amount of information needed
Characteristics of stimulus or concept Application context Capacity of scale

49 Which scale to use? Amount of information needed
Characteristics of stimulus or concept Application context Capacity of scale Post-measurement analysis

50 Which scale to use? Amount of information needed
Characteristics of stimulus or concept Application context Capacity of scale Post-measurement analysis Statistics are designed for specific types of scales. Using the wrong scale will give answers that are nonsense.

51 Measurement Characteristics:
Lecture 7B Measurement Characteristics:

52 Measurement characteristics:
Y = x(true) + x(sy-error) + x(random)

53 Measurement characteristics:
Y = x(true) + x(sy-error) + x(random) Systematic error can be eliminated.

54 Measurement characteristics:
Y = x(true) + x(sy-error) + x(random) Random error cannot be eliminated.

55 Measurement characteristics:
Y = x(true) + x(sy-error) + x(random) If a sample is taken to estimate an answer: another form of error is added……

56 Measurement characteristics:
This is called a Sampling Error Y = x(true) + x(sy-error) + x(random) + x(sampling error) If you take a sample… you will create a sampling error!

57 You and a friend (in the same class) take the
same exam at the same time and get different grades.

58 WHY?

59 Take a piece of paper… write down five different reasons why these two friends taking the same class would get different grades... What then did the grade actually measure? Write down a definition of a “grade.” If you suggested that a “grade” is a measurement of what a student knows, how many “grades” would you suggest need to be taken in order to be confident that the student actually knows what the grades indicate that they know?

60 Measurement characteristics:
Validity Before validity can be established, it is necessary to show that measurements have reliability. A measurement can be reliable without being valid, but it cannot be judged to be valid without reliability.

61 Measurement characteristics:
Reliability

62 Measurement characteristics:
Reliability Stability

63 Measurement characteristics:
Reliability Stability Test-retest Equivalent forms

64 Measurement characteristics:
Reliability Stability Test-retest Equivalent forms 2. Equivalence

65 Measurement characteristics:
Reliability Stability Test-retest Equivalent forms 2. Equivalence a. Kuder-Richardson b. Cronbach’s Alpha

66 Measurement characteristics:
Reliability Stability Test-retest Equivalent forms 2. Equivalence a. Kuder-Richardson b. Cronbach’s Alpha Lee Cronbach

67 Measurement characteristics:
Reliability Stability Test-retest Equivalent forms 2. Equivalence a. Kuder-Richardson b. Cronbach’s Alpha Learn, Effective, & Like the instructor

68 Measurement characteristics:
Reliability Stability Test-retest Equivalent forms 2. Equivalence a. Kuder-Richardson b. Cronbach’s Alpha 3. Inter-rater Consistency a. Krippendorff’s Alpha Klaus Krippendorff 1932 -

69 Measurement characteristics:
If a measurement is reliable, it may be valid: But there are many ways that a measurement could be valid or invalid.

70

71 Measurement characteristics:
Validity Face validity

72

73 Measurement characteristics:
Validity Face Content

74

75 Measurement characteristics:
Validity Face Content Criteria

76 Measurement characteristics:
Validity Face Content Criteria a. Concurrent b. Predictive

77

78 Measurement characteristics:
Validity Face Content Criteria a. Concurrent b. Predictive 4. Construct

79

80 Measurement characteristics:
Validity Face Content Criteria a. Concurrent b. Predictive 4. Construct a. Convergent

81 Measurement characteristics:
Validity Face Content Criteria a. Concurrent b. Predictive 4. Construct a. Convergent b. Divergent

82 Measurement characteristics:
Validity Face Content Criteria a. Concurrent b. Predictive 4. Construct a. Convergent b. Divergent c. Discriminant

83 Measurement characteristics:
Validity Face Content Criteria a. Concurrent b. Predictive 4. Construct a. Convergent b. Divergent c. Discriminant d. Nomological

84 Measurement characteristics:
Validity Face Content Criteria a. Concurrent b. Predictive 4. Construct 5. Utilitarian (?) A measurement may satisfy a utilitarian goal independently of any validity of the actual measurement.


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