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04/08/23 Dalia Mostafa 2
Introduction
There are several types of research studies.
All research studies can be classified under
two main categories: the qualitative versus the
quantitative.
04/08/23 Dalia Mostafa 3
Introduction
The qualitative approach involves the collection of narrative data in order to gain insights into a phenomenon of interest; data analysis includes the coding of the data and production of verbal synthesis (inductive process).
e.g. Historical Research
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Introduction
The quantitative approaches involve the
collection of numerical data in order to
explain, predict and/or control a phenomenon
of interest; data analysis is mainly statistical
(deductive process).
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Introduction
Such as:
-The Correlational Research
-The Experimental Research
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The Correlational Research
Definition:
The correlational research attempts to
determine whether and to what degree, a
relationshiprelationship exists between two or more
quantifiable (numerical) variables.
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The Correlational Research
You collect data on at least two variables for
the same group of subjects and then calculate a
correlation coefficient between the two
variables.
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What is a Correlation Coefficient?
A correlation coefficient is a number between
-1 and 1 which measures the degree to which
two variables are linearly related.
It is represented by the letter (r).
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What is a Correlation Coefficient?
If there is perfect linear relationship with positive
slope between the two variables, we have a
correlation coefficient of 1.
r = 1
If there is positive correlation, whenever one
variable has a high (low) value, so does the other.
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What is a Correlation Coefficient?
If there is a perfect linear relationship with negative slope between the two variables, we have a correlation coefficient of -1.
r = -1 If there is negative correlation, whenever one
variable has a high (low) value, the other has a low (high) value.
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What is a Correlation Coefficient?
A correlation coefficient of 0 means that there is no linear relationship between the variables (null).
r = 0
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What is a Correlation Coefficient?
To understand what is a correlation
coefficient, follow these links and move the
curser: http://noppa5.pc.helsinki.fi/koe/flash/corr/corrx2-en.html
http://noppa5.pc.helsinki.fi/koe/corr/cor7a/cor7a.html
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What is a variable?
Variable: a defined characteristic that varies; it
has at least two values and usually more.
For example, anxiety about writing in a second
language is a variable, because it varies across
students.
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What is a measure?
To assign a value to the degree of anxiety that
students feel, they are given a test (measure)
of writing anxiety.
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Examples of Correlational Research
The relationship between intelligence and self-
esteem
The relationship between anxiety and
achievement
The relationship between using an aptitude test
and predicting success in an algebra course
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Examples of Correlational Research
A group of high school students took two tests
that required them to solve analogies to
recognize antonyms (relationship).
The researchers discovered a correlation
between students’ abilities to complete
analogies correctly and to identify antonyms.
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Examples of Correlational Research
In general, students who were good at one task
were also good at the other; students weak in
one task were weak in the other.
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An Important Note
In correlational research, no attempt is made to
state that one thing causes another, only that
one thing (one variable) is predictable from
the other.
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Validity
A measure (test) is valid if it measures what it is intended to measure.
To demonstrate the validity of a test we want to show that scores on the test correlate highly with some external measure of what the test purportedly measures.
This external measure is referred to as the criterion.
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Reliability
The reliability of a measure refers to the
accuracy or consistency of the measurement.
There are many sources of error that can
reduce the accuracy of measurements.
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Reliability In such cases, it is important to provide
evidence that the observations or ratings are reliable.
This is accomplished by determining interrater reliability, sometimes called interobserver reliability or interjudge reliability.
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Reliability
To do this, two or more persons rate the same
phenomenon.
Their ratings are then compared to see how
well they agree with one another.
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Recap
The Qualitative & Quantitative approaches
The definition of the correlational research
The definition of the correlational coefficient: Positive,
Negative & Null
What is a variable?
What is a measure?
The validity & reliability of a correlational research