1. Info 2040 Foundation of Quantitative Analysis
Week 2-1

2. Class Activities
Think of a question that lead you to collecting a data set (comprising of data and cases)
Eg. What types of telecommunication operators do students in info 2040 subscribed to? Or what are the weights of the students in this class?
Create a data set (a minimum of 50 cases) in the Excel spreadsheet
Arrange them as data and cases
You may find your data in the internet – describe what the data is about, or for what purpose

3. Measurement The form in which our data represented
What do we normally measure?
How do we measure
What kind of measurements can you find out there?
Why do we measure?
Most of the time we measure variables
What is a variable?

4. Measurement and Variable
Measurement – the use of any rule to assign numbers to cases so as to represent the presence or absence or quantity of some attribute possessed by each case
Variable – an attribute or characteristic that varies from one case to the next

5. Rules in Measuring Very important Depend on what is being measured
More than one way to measure an attribute
Sometimes called “scale” or “level” or measurement
Will determine how we choose the statistical tools

6. Scale of Measurement
Nominal
Ordinal
Interval
Ratio

7. Nominal Scale The lowest level of measurement
Describes in terms of quality of each case – “what kind” NOT “how much”
Eg. Gender – male or female,
Describe presence or absence of an attribute – eg. Yes or NO
When assigned numbers, the difference has no mathematical value
How do we use statistics to describe data in this category?

8. Ordinal Scale Involves assigning numbers to cases
Conveys quantitative information about cases
Eg. Strongly agree = 1, Agree = 2, Somewhat agree = 3, Disagree = 4, Strongly disagree = 5
1 is < 2, 3 is > 2
2 – 1 ≠ 3 -2 (the different has no mathematical value)

9. Interval Scale
Scores on the scale variable determined by the number of fixed-sized units
No absolute 0 in the variable attribute
Arbitrary 0 point – 0 does not means complete absence of attribute
0 represents low quantity
The different can be mathematically manipulated – 2 -1 = 3 – 2 = 1
What are other examples of variables measured using interval scale?

10. Ratio Scale Highest, most flexible level of measurement
Data available themselves to all of most powerful statistical procedures
Similar to interval scale EXCEPT
0 means 0
What are the example of variables measured using ratio scale?

11. Assignment 2 In continuation with the data set earlier,
Complete the data sheet with at least 50 cases and at least 4 variables that are measured with nominal, ordinal, interval, and ratio scale.