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Introduction

There are several types of research studies.

All research studies can be classified under

two main categories: the qualitative versus the

quantitative.

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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