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.
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3. Is ‘education’ a
variable?
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4. Types of variables
Variables
Categorical
Nominal
Ordinal
Numeric
Continuous
Discrete
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5. Important
ORDINAL VARIABLES ARE OFTEN ANALYSED AS
NUMERIC VARIABLES.
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6. Data sources
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7. Learning Analytics
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▪ Grades
▪ Posts in discussion forums
▪ Clicks on different resources
▪ Time when students’ stop
watching videos

8. Questionnaires
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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.
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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?
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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...
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20. …or frequencies or percentages.
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21. When to use
percentages or
frequencies?
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22. Measures of central tendency
Mean
• Arithmetic
average
Median
• Central value
when data 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
▪ What measure of central tendency should we use in each
case? Why?
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18 18 19 20 21 21 21 21 22 42
18 18 19 20 21 21 21 21 22 22
Case 1
Case 2

24. Measures of dispersion
Range
• Difference
between the
highest value and
the smallest value
Variance
• Mean squared
distance between
each point and the
centre of the
distribution
Standard
deviation
• Square root of
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
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26. Describing the data is
part of descriptive
statistics.
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27. Quantitative
Research
@BRENDAPADILLA