Quantitative Research: Descriptive Statistics

In this session, we will discuss:
Types of variables
Data sources
Likert scales
Measures of central tendency
Measures of dispersion

1. Quantitative Research:
Descriptive Statistics
BRENDA CECILIA PADILLA RODRÍGUEZ

2. Key concepts
Data
•Observations &
measurements
•Often collected through
research
•Types: Quantitative &
qualitative
Variables
•Characteristics or
attributes observed or
measured
•The value of a variable
varies.
2

3. Is ‘education’ a
variable?
3

4. Typesofvariables
Variables
Categorical
Nominal
Ordinal
Numeric
Continuous
Discrete
4

5. Important
ORDINAL VARIABLES ARE OFTENANALYSEDAS
NUMERICVARIABLES.
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6. Data sources
6

7. Learning Analytics
7
▪Grades
▪Posts in discussion forums
▪Clicks on different resources
▪Time when students’ stop
watching videos

8. Questionnaires
8

9. Likert Scales
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10. Activity: Likert Scale
▪Check the following Likert scale.
▪How many errors can you find?
▪Discuss them in your small group.
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https://tinyurl.com/likert-oops

11. Developing an accurate
Likert scale is a process.
11

12. What is an advantage
of Likert scales?
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13. What is a disadvantage
of Likert scales?
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14. Ok. So we
applied a Likert
scale, got some
answers… What
now?
14

15. One column per item,
one row per participant
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16. Identify and get rid of mistakes
People who did not agree to answer the survey (?!)
Duplications
Severely incomplete answers
Strange or inconsistent answers
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17. Activity: Data analysis
▪Check the following answers to a Likert scale.
▪How would you analyse it?
▪Discuss the interpretation of your findings in your group.
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https://tinyurl.com/likert-analysis

18. 18
What does it
mean to have a
result such as an
average of 3.4?

19. We need points of reference...
19

20. …or frequencies or percentages.
20

21. When to use
percentages or
frequencies?
21

22. Measuresofcentral tendency
Mean
•Arithmetic
average
Median
•Central value
whendata is
ordered
Mode
•Most
frequently
repeated
value
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They aim to identify the most representative value of a data set, the
centre of a distribution.

23. Activity: Examples
▪Whatmeasureofcentral tendencyshouldweuse in each
case? Why?
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18181920212121212242
18181920212121212222
Case 1
Case 2

24. Measuresofdispersion
Range
•Difference
betweenthe
highestvalueand
thesmallestvalue
Variance
•Mean squared
distancebetween
eachpointand the
centre ofthe
distribution
Standard
deviation
•Square rootof
variance
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They aim to measure of the spread of the data around the centre of
the distribution..

25. Standard Deviation: Overview
25

26. Describingthedata is
partofdescriptive
statistics.
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27. Quantitative
Research
@BRENDAPADILLA